Malaysia's ruling party has set the ball rolling for the dismissal of a former deputy prime minister and the former Kedah mentri besar after they openly called for the ouster of Prime Minister Najib Razak.

As the supreme council of the United National Malay Organisation (UNMO) meets the dismissal of Muhyiddin Yassin and Mukhriz Mahathir is all but a foregone conclusion, party insiders have said.

Unmo factions have also called for stripping former prime minister Mahathir Mohamd of all government privileges after he became the rallying point of the anti-Najib move, The Star newspaper reported.

Puad Zarkashi, Umno supreme council member, said a motion seeking the expulsion of Muhyiddin and Mukhriz will be moved in the next council meeting.

"Their decision to 'bersekongkol' (conspire) with DAP was done deli­berately. It is a betrayal against what Umno has been fighting all this while, which is to reject DAP's agenda," Puad said.

Mahathir Mohamad, a long-time critic of the tainted prime minister, resigned from the party last week, saying Najib shoud be removed from power.

In a surprise move, prominent opposition figure and Mahathir's arch rival Anwar Ibrahim offered support to the former prime minister.

As many as 58 prominent leaders joined ranks with Mahathir issuing a signed memorandum, the Citizens' Declaration', calling for the resignation of Najib.

Najib is reeling from allegations that he diverted hundreds of millions of dollars from the state-owned company into his personal account in the run up to the 2013 election.

More than $1 billion was deposited into Najib's account between 2011 and 2013, the Wall Street Journal reported last week, citing people familiar with the ongoing investigations.

Najib, defiant in the face of rising momentum in the opposition, said the move led by Mahathir and followers was a mistake.

"I see most of the Umno leaders, they are very angry and disappointed with Mahathir's decision to work with the opposition," the prime minister said.

He said his government has the mandate and it will focus on development projects.

"As far as we are concerned, the confidence level depends on elections. At the moment, the government will continue because we have the mandate and numbers in Parliament. The party is also behind the government," he said, according to Malaysia Kini.