Singapore is cooperating with authorities in Malaysia, Switzerland and the US who are investigating 1MDB, said the Monetary Authority of Singapore (MAS) and the Commercial Affairs Department, the city-state's white-collar crime agency.
"In connection with these investigations, we have sought and are continuing to seek information from several financial institutions, are interviewing various individuals, and have seized a large number of bank accounts," the two agencies said in a joint statement.
The statement did not offer any further details. In July, local police said they had only frozen two bank accounts linked to the 1MDB probe.
The statement comes a week after Switzerland's chief prosecutor said a criminal investigation into 1MDB had revealed that about $4bn appeared to have been misappropriated from Malaysian state companies.
1MDB, whose advisory board is chaired by Malaysian Prime Minister Najib Razak, has been investigated by Malaysian authorities following accusations of financial mismanagement and graft. 1MDB has denied these allegations.
Last week, Malaysia's attorney general cleared Najib of any criminal offences or corruption, declaring that $681mn deposited into his personal bank account was a gift from Saudi Arabia's royal family and no further action needed to be taken.
The Monetary Authority of Singapore has been in touch with Malaysian regulators since last year, when Malaysia's government said 1MDB had redeemed $1.1bn from the Cayman Islands and placed it in the Singapore unit of Swiss private bank BSI.
BSI has declined to comment.
The Wall Street Journal reported last year that investigators had traced nearly $700mn from an account at Falcon Private Bank in Singapore to accounts in Malaysia they believed belonged to the prime minister.
Falcon Private Bank, a Swiss private bank owned by Abu Dhabi sovereign wealth fund International Petroleum Investment Company, has said it is in contact with Singapore's central bank and will cooperate with authorities.
