The Malaysian Anti-Corruption Commission (MACC) is expected to record Prime Minister Najib Abdul Razak's statement regarding the colossal sum transferred into his personal bank accounts.

Quoting a source, Reuters reported that MACC would quiz the premier over the funds from SRC International.

Najib earlier made a commitment to give a statement to the anti-graft agency and his office is also expected to take queries on the matter in Parliament later in the day.

The prime minister has denied any wrongdoing or abusing public funds for personal gain. He has also claimed there is a conspiracy to topple him.

The prime minister has complained the investigation caused "various accusations and slander".

A spokeperson at the Prime Minister's Office did not confirm whether Najib would be questioned by the MACC today, but said he had made a commitment to give a statement.

MACC is probing the RM2.6 billion and RM42 million discovered in his accounts, which came to light when the Wall Street Journal and Sarawak Report exposed the matter.

Najib claimed that the RM2.6 billion, transferred prior to the last general election, was a political donation from a middle eastern source, which was also confirmed by the MACC.

Meanwhile, the SRC funds amounting to RM42 million was transferred through its subsidiaries into Najib’s accounts late 2014 and early this year.

SRC, which is a former 1MDB subsidiary, is a Finance Ministry-owned firm. Najib is also the finance minister.

Najib is also chairperson of the 1MDB advisory board. The fund is also being investigated by law enforcement agencies in Switzerland, Hong Kong and the United States, media and sources have said.

Opposition leaders and some establishment figures, including former prime minister Dr Mahathir Mohamad, have urged that Najib resign over his alleged involvement in the issue.

Critics also accused the government of dragging its feet on the investigation and even the sultans have called for a quick and transparent investigation.

At the end of August, tens of thousands of Malaysians rallied to call for Najib's resignation.

The controversy has battered Malaysian markets, with the ringgit losing about a quarter of its value to become Asia's worst-performing currency this year.