The Internal Security Act 1960 (ISA) of Singapore is a statute that grants the executive power to enforce preventive detention, prevent subversion, suppress organised violence against persons and property, and do other things incidental to the internal security of Singapore. The present Act was originally enacted by the Parliament of Malaysia as the Internal Security Act 1960 (No. 18 of 1960), and extended to Singapore on 16 September 1963 when Singapore became a state of Malaysia.
Before a person can be detained under the ISA by the Minister for Home Affairs, the President must be satisfied that such detention is necessary for the purposes of national security or public order. In the landmark case of Chng Suan Tze v. Minister for Home Affairs (1988), the Court of Appeal sought to impose legal limits on the power of preventive detention by requiring the government to adduce objective facts which justified the President's satisfaction. Two months after the decision, a series of legislative and constitutional amendments was enacted that effectively reversed the Chng Suan Tze decision. These amendments were subsequently confirmed to be valid by the High Court and Court of Appeal in Teo Soh Lung v. Minister for Home Affairs (1989–1990), which held that it was sufficient for the President to be subjectively satisfied that a detainee is a threat to national security in order for a detention order to be issued under the ISA.
Notable ISA cases include Operation Coldstore in 1963, which led to the arrests of more than 100 left-wing politicians and trade unionists, including members of socialist opposition party Barisan Sosialis. Chia Thye Poh, an alleged Communist, was detained and subject to other restrictions on his liberty under the ISA from 1966 to 1998. The Chng Suan Tze and Teo Soh Lung cases resulted from a 1987 security operation called Operation Spectrum, in which 22 individuals were arrested and accused of being members of a Marxist conspiracy. The ISA also empowers the authorities to prohibit political and quasi-military organisations, ban subversive documents and publications, shut down entertainments and exhibitions that are or are likely to be detrimental to the national interest, and to suppress organised violence by declaring parts of Singapore to be security areas.
History and developments British colonial Malaya introduced the Emergency Regulations Ordinance 1948Emergency Regulations Ordinance 1948 (No. 17 of 1948). on 7 July 1948 during the Malayan Emergency in response to a Communist uprising and guerrilla war. The regulations allowed the police to arrest anybody suspected of having acted or being likely to act in a way that would threaten security without evidence or a warrant, hold them incommunicado for investigation, and detain them indefinitely without the detainee ever being charged with a crime or tried in a court of law.. In 1955, the Emergency Regulations were succeeded by the Preservation of Public Security Ordinance (PPSO),Preservation of Public Security Ordinance 1955 (No. 25 of 1955) ("PPSO"). which was introduced by the Labour Front government as a result of the 1955 Hock Lee bus riots. Strong criticism of the PPSO came by the then-opposition People's Action Party (PAP). In 1958, the PAP's Lee Kuan Yew accused the Lim Yew Hock government of using the PPSO to stifle political dissent..
In 1960, three years after Malaya's independence, the Emergency was declared over. However, the Malayan Internal Security Act 1960 (ISA)Internal Security Act 1960 (No. 18 of 1960, Malaya) ("ISA"). was passed in place of the PPSO with much of the same powers. During parliamentary debates on the Act, Malayan prime minister Tunku Abdul Rahman stated that the ISA would only be applied against only the remaining Communist insurgents. The Malayan Communist Party (MCP) and its insurgents eventually surrendered in 1989. The Malayan ISA was drafted by British lawyer Hugh Hickling; in 1989, he commented his displeasure of its use "against political opponents, welfare workers and others dedicated to nonviolent, peaceful activities".. When Singapore formed the federation of Malaysia – together with Malaya, Sabah, and Sarawak – in 1963, the Malayan ISA was extended to Singapore. The Act was retained in Singapore even after its separation from Malaysia in 1965. The current version of the Act is known as Chapter 143 of the 1985 Revised Edition. ("ISA").
In September 2011, the debate over whether the ISA should be retained was re-opened after Malaysia announced that it was considering repealing the ISA.. Malaysian prime minister Najib Razak stated that the Act would be abolished and replaced by new laws to safeguard peace and order.. The ISA was finally replaced and repealed by the Security Offences (Special Measures) Act 2012 on 31 July 2012 in Malaysia. The legitimacy and relevance of the ISA were subsequently debated by former ISA detainees, the Singapore government, and others.; . On 18 October 2011, Singaporean politician Janil Puthucheary stated in Parliament that although he was uncomfortable with detention without trial, he believed national security should take priority. However, he did support including stronger protections against the Act's misuse and discussing it more openly..
The following day, deputy prime minister and home affairs minister Teo Chee Hean explained the relevance of the ISA and its powers of preventive detention, as it had initially been used against communist threats in the 1960s and was later used against espionage and terrorism. He stated that preventive detention allowed authorities to act against security threats before they were committed, particularly in cases involving confidential information that could not be publicly disclosed.. Opposition political parties have called for the ISA to be abolished. In its manifesto for the 2011 general election, the Workers' Party (WP) said that specific anti-terrorism and anti-espionage laws, which allow arrests and detention without trial only under strict conditions, should be enacted to replace the ISA.. The National Solidarity Party took a similar stance in February 2013.. Ahead of the 2025 general election, the WP again included repealing the act in its manifesto.
Legislative authority for enactment The legislative authority for the enactment of the ISA is Article 149 of the Constitution of Singapore,. which appears in Part XII ("Special Powers against Subversion and Emergency Powers").See . Entitled "Legislation against subversion", Article 149 states:
To satisfy the requirements of Article 149(1), the preamble to the Malaysian ISA, which has been retained in Singapore's ISA, contains the following recital:
Provisions relating to internal security Part II of the ISA, the first substantive part of the Act, contains provisions relating to internal security.Part I is entitled "Preliminary" and contains the short title of the Act and an interpretation section. It is divided into six chapters:
I. Prohibition of organisations and associations of a political or quasi-military character and uniforms, etc. II. Powers of preventive detention. III. Special powers relating to subversive publications, etc. IV. Control of entertainments and exhibitions. V. Other powers for the prevention of subversion. VI. Miscellaneous.
Prohibition of political or quasi-military organizations Chapter I of Part II of the ISA empowers the Minister for Home Affairs to take action against political or quasi-military organisations and associations. It is a criminal offence to be a member or adherent of any association of persons who are organised, trained, or equipped to enable them to be employed "in usurping the functions of the police or of the Singapore Armed Forces" or "for the purpose of enabling them to be employed for the use or display of physical force in promoting any political or other object, or in such a manner as to arouse reasonable apprehension that they are organised or trained or equipped for that purpose". It is a more serious crime to promote or conspire with someone else to promote, or to participate in the control or management of, the association, or to organize or train any member or adherent of the association.ISA, s. 5(1).
The Minister is empowered to prohibit any clothing worn in public by members or adherents of a political or quasi-military association involved in such activities, or any clothing indicating an association with a political organisation or with the promotion of a political object.ISA, s. 3. Wearing such clothing is considered an offence.ISA, s. 4. In addition, if the Minister considers it to be in the national interest to do, he may prohibit the "manufacture, sale, use, wearing, display or possession of any flag, banner, badge, emblem, device, uniform or distinctive dress or any part thereof".ISA, s. 7(1). Currently, the only emblem or device that is prohibited is one "in the form of a 5-pointed red star or a hammer and sickle in circumstances which raise a reasonable presumption that the emblem or device was intended or was likely to be used in a manner prejudicial to the interests of Singapore or to promote or foster a purpose prejudicial to or incompatible with peace, welfare or good order in Singapore"..
It is a crime to be present at or to attend any meeting or assembly that aims to train or drill participants "in the use of arms [...] or for the purpose of practising military exercises, movements or evolutions". It is also a crime to train or drill others in these manners or to take part in the control or management of an association whose members are so trained. The prohibition does not apply to members of the Singapore Armed Forces, the police, a legally constituted volunteer or local force, a visiting force lawfully present in the country, or any organisation or association exempted by the Minister.ISA, s. 6.
Preventive detention Chapter II of Part II of the ISA, which allows for preventive detention (also known as detention without trial), is the most conspicuous feature of the Act. It confers on the executive a discretionary power to arrest and detain without trial, when necessary, a person with a view to prevent "that person from acting in any manner prejudicial to the security of Singapore or any part thereof or to the maintenance of public order or essential services therein".ISA, s. 8(1)(a). For the purposes of this provision, essential services means services relating to water, electricity, public health, fire, prisons, post, telephony, telegraphy, radio communication (including broadcasting and television), ports, docks, harbours, public transport, and the bulk distribution of fuel and lubricants.ISA, s. 8(3) and the 3rd Schedule. Instead of detaining a person for the purposes mentioned above, the executive may impose other restrictions upon the person's liberty such as curfews, requiring the reporting of their movements, prohibiting the person from speaking at public meetings or taking part in political activities, and travelling beyond Singapore or any part of the country.ISA, s. 8(1)(b).
Procedure
Before a person can be detained under the ISA, the President must be satisfied that such detention is necessary for the purposes of national security or public order.ISA, s. 8(1). This is a precondition for the valid exercise by the Minister for Home Affairs of the power to order the detention.Chng Suan Tze v. Minister for Home Affairs SGCA 16, 2 S.L.R.(R.) [Singapore Law Reports (Reissue)] 525 at 537, para. 30, Court of Appeal (Singapore), archived from the original on 24 December 2011. The detention order is supplemented by section 74 of the ISA which empowers the police to arrest and detain any person pending enquiries without a warrant under section 8.ISA, s. 74(a).