SINGAPORE - From Tuesday (May 1), 21 new psychoactive substances (NPS) will be reclassified as Class A controlled drugs, the Central Narcotics Bureau (CNB) said on Monday.

They will be moved up from the fifth schedule of the Misuse of Drugs Act (MDA), which allows the seizure of such substances, to the first schedule, which constitutes an offence if anyone is convicted of dealing with the substances.

Additionally, another four NPS will be classified directly as Class A controlled drugs under the Act.

NPS refer to substances which produce similar effects as controlled drugs such as cannabis, cocaine, Ecstasy, methamphetamine or heroin.

Among the NPS to be reclassified as Class A controlled drugs are ADBICA, a designer drug identified in synthetic cannabis blends; Methylbenzylpiperazine or MBZP, a stimulant drug sold as an ingredient in recreational drugs; and 25C-NBOH, a synthetic psychedelic substance that produces stimulating psychedelic effects.

Anyone found guilty of trafficking, manufacturing, importing, exporting, possessing, or consuming these substances will face penalties under the MDA, CNB said in a statement on Monday.

Anyone convicted of trafficking Class A controlled drugs will face at least five years' jail and five strokes of the cane.

Those who reoffend or sell drugs to young or vulnerable people will also be liable for enhanced penalties.

CNB will also be empowered to subject NPS abusers to supervision, commit them to a drug rehabilitation centre for treatment and rehabilitation, or charge them in court.

CNB will also be listing five NPS in the fifth schedule of the MDA.

The fifth schedule allows CNB to control and prevent proliferation of NPS, allowing CNB to seize them. However, dealing in or consuming substances in the fifth schedule do not constitute offences under MDA until they are listed as controlled drugs in the first schedule.

The move comes after CNB reclassified four NPS as Class A controlled drugs from May 1 last year (2017).

CNB said there has been a "rapid increase in the number, type and availability of NPS across the globe".

Based on a report released in March by the United Nations Office on drugs and crime, there were at least 779 NPS identified by end-2017.

"Many of these NPS have been reported in overseas journals to have no licit medical use," said CNB. "Their abuse has been linked to adverse physical and psychological reactions, including paranoia, seizures, hallucinations and even death."

CNB said it regularly reviews strategies to improve detection and regulation of NPS, including regularly listing NPS that have emerged in the market.

"A significant proportion of the NPS reported overseas are currently controlled under the MDA," CNB said.