The monarch acknowledged that Anwar had sought his audience on the plan, but that the meeting was postponed as he was convalescing in hospital after taking ill on Tuesday.

Anwar, in a hastily convened press conference at noon, said he had been approached to take over the government by “a number of MPs from various parties who expressed deep dissatisfaction with the current leadership”.

While stressing that he had “convincing support” from the country’s 222 MPs, the 73-year-old opposition leader did not provide an exact figure. He said the move had been in the works for a month.

The prime minister’s response, which came by way of a written statement in the late afternoon, did not strike a particularly defiant note.

“Until proven otherwise, the Perikatan Nasional government is standing firm and I am the legitimate prime minister,” Muhyiddin said.

Malaysia’s Anwar pans Muhyiddin’s Covid-19 economic rescue plan

There were reactions from his ministers as well.

Khairy Jamaluddin, the science, technology and innovation minister, tweeted a photo of a cabinet meeting earlier on Wednesday with the caption: “Cabinet meeting just ended. Nothing fell or collapsed.”

Azmin Ali, Muhyiddin’s No. 2 in the cabinet and an Anwar ally-turned-rival, tweeted: “Incorrigible liar and political psychopath.”

Anwar, leader of the three-party Pakatan Harapan alliance, said he hoped to meet with Sultan Abdullah soon to prove his majority.

Anwar said the new administration would have a “strong, formidable [and] convincing majority”.

“I am not talking about four, five, six – I am talking about much more than that,” Anwar said, saying the final figure of MPs who backed him amounted to “close to” two-thirds of all MPs.

Anwar said Muhyiddin “has fallen as PM [and] I invite him to work with us”.

He said the prime minister’s cooperation would “facilitate a peaceful transition”, and added that there was a possibility he could “continue to serve in a relevant role” in the new administration.

The final details would only be revealed after his audience with the king, Anwar said.

Anwar has been in politics since 1982, and was deputy prime minister for five years until he was sacked by Mahathir in 1998 during the elder statesman’s first stint in power.

Later, Anwar was jailed over sodomy and corruption on charges he maintains were trumped up.

Upon his release, he galvanised the country’s opposition to a potent force. Wednesday’s development rekindled memories among online commentators of Anwar’s claim in 2008 that he had a majority to topple then Prime Minister Abdullah Ahmad Badawi.

The move later fell flat as members of the long-ruling United Malays National Organisation (Umno) failed to defect.

He was later jailed again – also on charges he claimed were false – and was incarcerated when Pakatan Harapan won the 2018 vote. Soon after the landmark election, the then-sitting monarch Muhammad V granted him a royal pardon, paving the way for the fiery orator's return to frontline politics.

Mahathir eyes new role as power broker in Malaysian politics

Anwar hinted on Wednesday that his new alliance would include members of Umno, the linchpin party of the Barisan Nasional (BN) alliance that governed the country from 1957 until the 2018 election.

Umno’s chief Ahmad Zahid Hamidi in a statement said he was informed that “many” MPs from Umno and BN supported Anwar’s move. BN, with a total of 42 MPs, currently props up Muhyiddin’s razor-thin legislative majority.

Zahid in his statement said he respected the positions of MPs who now backed Anwar.

Another major question on the mind of commentators was Mahathir’s position on Anwar’s move. Asked during the press conference if he had the nonagenarian’s support, Anwar replied: “No, but he may decide later.”

Speaking in a virtual business conference before Anwar’s press conference, Mahathir raised doubts about whether his former protege’s hope of forming a government would materialise. The two men had set aside their decades-long rivalry when they were part of the Pakatan Harapan government, but have again drifted apart following the March coup by Muhyiddin.

“We will have to wait and see if this is another episode of making claims that cannot be substantiated,” Mahathir was quoted as saying by the business news portal The Edge.

Muhyiddin more popular than Mahathir, but not with Malaysian-Chinese: poll

On social media, commentators wondered aloud if Anwar’s plan to take over the government would fizzle out like in 2008. Following his press conference, Pakatan Harapan constituent parties Democratic Action Party (DAP) and Parti Amanah Negara (Amanah) said they backed Anwar’s plan to form a new government.

In total, the bloc has 91 MPs, 21 seats short of a simple majority in the legislature. The DAP has 42 seats, Amanah has 11 seats and Anwar’s multiracial Parti Keadilan Rakyat has 38 seats.

Shafie’s Parti Warisan Sabah (Sabah Heritage Party) faces a stiff challenge from Muhyiddin’s allies, the Gabungan Rakyat Sabah (Sabah People’s Alliance) in the polls.

Political observer Azmil Tayeb told This Week in Asia that Anwar’s plan would have little impact on the vote given that Warisan was already the “odds-on favourite” to win.

But it might add to the “jitters and insecurity felt by [Muhyiddin’s] government if it loses Sabah and also in the lead up to the budget vote in parliament later this year”, Azmil said.