Malaysia's Prime Minister Najib Razak faces the toughest test of his political career so far when parliament reconvenes next week, with the leader facing questions from a growing number of establishment figures about his alleged role in a graft scandal at the state investment fund.
Najib's tight grip on his United Malays National Organisation (UMNO) party has kept him in power despite public anger over alleged graft and financial mismanagement at strategic investment fund 1Malaysia Development Bhd (1MDB), whose advisory board the prime minister chairs.
But that grip appears to be loosening, and his position could become precarious if he loses some crucial upcoming votes in parliament.
Some senior leaders from UMNO, including former deputy prime minister and Najib's potential successor Muhyiddin Yassin, joined forces with influential former premier Mahathir Mohamad on Monday to criticise Najib and call on party members to "speak up" against wrongdoing.
Although they stopped short of openly calling for Najib's resignation, the rebellion may have opened up an opportunity the opposition is seeking to exploit through a no-confidence vote in parliament next week.
"We have decided in principle to move a no confidence motion in parliament," said Tian Chua, a member of parliament and National Vice President of opposition party PKR.
"We will definitely need to collaborate with some leaders from the ruling coalition. But now there is an opportunity to put aside other interests and focus on saving the country and the people."
A no-confidence vote is seen as having a slim chance of outright success given the opposition bloc is about 25 seats short of the majority needed to carry the motion. Even if it gets the numbers, the speaker of the house could reject the motion, stopping it from being tabled.