Treasurer-general Irwan Serigar Abdullah has been transferred to the Public Service Department (PSD) effective immediately, according to chief secretary to the government Ali Hamsa.

Ali said Irwan, who is also 1MDB chairperson, will no longer be allowed to carry out his duties as treasurer-general.

"Effective May 14 to June 13, the officer (Irwan) will be placed at the PSD and will not be allowed to carry out duties as treasurer-general or any matters relating to the Finance Ministry," Ali said in a statement this evening.

He added that Irwan's contract will also be shortened.

"Irwan was appointed as treasurer-general on a contract basis from March 7, 2017, to March 6, 2019.

"The government has decided to shorten his service contract to June 14, 2018," said Ali.

Irwan took over the chairmanship of 1MDB at a time when the company was plagued by a corruption scandal.

International investigators claimed at least US$4.5 billion was misappropriated from 1MDB and allegedly laundered through the US financial system.

The previous BN government had refused to acknowledge any wrongdoing.

However, the BN was swept out of power in the May 9 general election, ending its 61-year rule.

The new Pakatan Harapan government has vowed to investigate the matter.