PUTRAJAYA (THE STAR/ASIA NEWS NETWORK) - Prosecutors are set to charge former Prime Minister Najib Tun Razak and former 1MDB president Arul Kanda Kandasamy on Wednesday (Dec 12) over the tampering of the graft-tainted state investment fund's final audit report.

Sources said that the former prime minister will be charged with using his position to instruct the then Auditor-General to remove "certain things" from the report. Arul Kanda will be charged with abetting Najib.

The two are expected to be charged at the Kuala Lumpur Sessions Court.

On Nov 25, Auditor-General Madinah Mohamad revealed that the final audit report on 1MDB had been tampered with and that Najib had knowledge of it. She also disclosed that two crucial matters dropped from the report were on the presence of wanted businessman Low Taek Jho or Jho Low at a 1MDB board meeting as well as the financial status of 1MDB.

The changes to the 1MDB report were made on Feb 26, 2016, on grounds that it was a "sensitive issue".

The Malaysian Anti-Corruption Commission (MACC) had arrested Najib Razak on Monday (Dec 10) for his alleged role in the tampering of the audit report on 1Malaysia Development Berhad (1MDB).

He was arrested at around 11am at the MACC headquarters shortly after he arrived for a fresh round of questioning over the issue. MACC sources said the former premier would be released if he could come up with money for bail.

Najib had spent about four hours at the office last Thursday (Dec 6), giving his statement to assist in the same probe.

The MACC has questioned several people about the report tampering, including former legal officer in the Attorney-General's Chambers Dzulkifli Ahmad, former Auditor-General Ambrin Buang, former chief secretary to the government Ali Hamsa, and the then 1MDB group president and chief executive officer Arul Kanda Kandasamy.

After Najib's arrest, his daughter Nooryana Najwa lamented his arrest on her mother Rosmah Mansor's 67th birthday.

"I know today is not the easiest day for us but let's take a moment to thank Allah that we are all healthy, alive and still able to help others in need," said Nooryana in a message on Instagram accompanied by a photo of her mother Rosmah carrying her when she was a child.

"Happy Birthday to my one and only Mummy. Love will get us through it all."