The Australian Federal Police (AFP) said on Tuesday they are working with international law enforcement agencies to investigate companies associated with Malaysia's scandal-hit sovereign wealth fund.

1Malaysia Development Bhd (1MDB), founded by Malaysian Prime Minister Najib Razak, is the subject of money laundering investigations in at least six other countries, including Switzerland, Singapore and the United States.

Civil lawsuits filed by the U.S. Department of Justice allege more than $3.5 billion was misappropriated from 1MDB. The lawsuits seek to seize $1 billion in assets allegedly siphoned off from 1MDB and diverted into luxury real estate in New York, Beverly Hills and London, valuable paintings, and a private jet.

Najib, who also chaired 1MDB's advisory board, has denied wrongdoing and said Malaysia would cooperate with international investigations. 1MDB has also denied wrongdoing.

The AFP is responsible for investigating breaches of proceeds of crime laws by Australian companies, citizens and residents.

"The AFP is aware of allegations relating to companies associated with 1MDB and have assisted our foreign law enforcement partners with their investigations in relation to a number of these matters," the AFP said in an emailed statement.

"As the AFP continues to evaluate these allegations it would not be appropriate to provide any further comment at this time," it said.

The AFP did not respond to Reuters' questions about reports they were investigating whether any financial gains from the scandal were in Australia or with which international agencies it was working.

Singaporean authorities have frozen the assets of Malaysian financier Low Taek Jho, commonly known as Jho Low, who has not been charged with any offence related to 1MDB but has been identified as a person of interest in related investigations.

Singapore prosecutors filed 16 charges last week against the former local branch manager of Swiss-based Falcon Private Bank AG as part of its investigation into 1MDB.

Authorities in the city-state jailed two former bankers from Swiss wealth manager BSI last year on charges including forgery and failure to disclose suspicious transactions involving Jho Low.