In 2012, the Singaporean Government introduced new legislation (Misuse of Drugs (Amendment) Act No. 30 of 2012) (in force since 01 May 2013) to allow temporary bans (up to 12 months) of NPS and empower enforcement officers to seize and destroy these substances. This amendment created a Fifth Schedule to include those substances placed under temporary control. However, the trafficking, manufacture, import, export, possession or consumption of any substance which is temporarily listed in the Fifth Schedule will not constitute an offence under the MDA, until that substance is removed from the Fifth Schedule and is subsequently listed as a controlled drug in the First Schedule whereupon all these offences will apply. According to the new section 58A, the Minister may, by order published in the Gazette, amend the Fifth Schedule by specifying any drug as a temporarily listed (up to 24 months) drug in that Schedule if that drug is not specified in Part I, II or III of the First Schedule. Several NPS and generic classifications of synthetic cannabinoids are included in the temporary schedule, including JWH-compounds, AM- compounds, CP compounds, etc. In May 2014, several NPS listed in the Fifth schedule were reclassified as Class A drugs and more NPS were included in the Fifth Schedule (Annex B for NPS under temporary control).

In April 2015, the Central Narcotics Bureau (CNB) announced that with effect on 1 May 2015, 18 substances (MAB-CHMINACA; 5-Fluoro-ADB-PINACA) and its fluoro positional isomers in the pentyl group; ADB-PINACA; 5-Chloro-AB-PINACA and its chloro positional isomers in the pentyl group; AB-CHMINACA; 5-Fluoro-AB-PINACA and its fluoro positional isomers in the pentyl group; AB-PINACA; PX-2 and its fluoro positional isomers in the pentyl group; PX-1 and its fluoro positional isomers in the pentyl group; 5-EAPB and its 4-yl, 6-yl and 7-yl isomers; 2C-H and its dimethoxy positional isomers in the phenyl ring; α-Methyltryptamine; 5-IT and its 4-yl, 6-yl and 7-yl isomers; 2C-I and its dimethoxy andiodo positional isomers in the phenyl ring; 5-MeO-DALT; MDMB-CHMINACA; MA-CHMINACA and 5-Fluoro-AMB and its fluoro positional isomers in the pentyl group) were going to be listed in the Fifth Schedule of the MDA, and therefore placed under temporary control.