Singapore has seized a large number of bank accounts in recent months as part of an investigation into possible money-laundering linked to Malaysian state investment fund 1Malaysia Development Berhad (1MDB), authorities said.

Singapore is cooperating with authorities in Malaysia, Switzerland and the United States 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.

"Since the middle of last year, the Commercial Affairs Department and the Monetary Authority of Singapore have been actively investigating possible money-laundering and other offences carried out in Singapore," they said.

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 after Switzerland's chief prosecutor said a criminal investigation into 1MDB had revealed that about $4 billion appeared to have been misappropriated from Malaysian state companies.

In a statement, 1MDB said it had not been contacted by Singapore authorities.

"As we have previously stated, 1MDB has not been contacted by any foreign legal authorities on any matters relating to the company," it said, adding that 1MDB remains committed to fully cooperating with any lawful authority and investigation.

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.

Malaysia's attorney general cleared Najib of any criminal offences or corruption, declaring that $681 million 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 $1.1 billion 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 $700 million 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.