Singapore's central bank on Monday formally launched a unit to fight money laundering, strengthening the financial hub's safeguards against illicit fund flows.

Officials of the Monetary Authority of Singapore (MAS) have said plans to create the special unit predated a continuing scandal involving state fund 1Malaysia Development Berhad (1MDB) in neighbouring Malaysia and banks operating in Singapore.

"But these recent developments have indeed underscored the merits of bringing together supervisory resources from across MAS to give a centralised focus on combating money laundering," a spokesman for the MAS said in June when it announced the creation of the unit.

Singapore last year opened an investigation into fund flows linked to 1MDB. In May this year it expelled Switzerland's BSI Bank for "gross misconduct" related to the Malaysian fund.

Last month Singapore revealed it had seized nearly US$180 million in assets through its investigations into suspected fraud and money-laundering linked to 1MDB.

The MAS on Monday confirmed it was examining the extent of Goldman Sachs Singapore's involvement in 1MDB bond deals.

US regulators last week said they had issued subpoenas to the American investment bank asking for documents related to its dealings with 1MDB.

"As our financial centre grows in scale, sophistication, and connectivity, so does the risk of criminal elements abusing our financial system," MAS managing director Ravi Menon said in June.

"We will strengthen our supervision of financial institutions’ controls to combat money laundering and illicit financing. And we will enhance our enforcement capability to deter poor controls or criminal behaviour in the industry."