KUALA LUMPUR - Former Malaysian prime minister Mahathir Mohamad is seeking to move a no-confidence motion in Parliament against his successor, Tan Sri Muhyiddin Yassin, when Parliament convenes on May 18.

The letter dated May 4 sent by Tun Dr Mahathir to the Speaker of Parliament's Lower House, Tan Sri Mohamad Ariff Md Yusof, stated his intention to table the motion as Mr Muhyiddin does not have the majority support of Members of Parliament to remain as prime minister.

It comes after Sabah Chief Minister Shafie Apdal earlier sought a motion of confidence in Dr Mahathir in a letter to Mr Ariff that went viral on social media late on Wednesday (May 6).

But the motion by Datuk Seri Shafie, who is Member of Parliament for Semporna in Sabah, was rejected by the Speaker as it was not in line with Article 43 of the Federal Constitution, which relates to the authority of the king to appoint the prime minister.

"Therefore, I will not allow the motion to be brought to the sitting," Mr Ariff said in response.

Mr Shafie earlier on Thursday confirmed that he had sent the letter, dated May 1, to the Speaker after being pressed by reporters in Sabah. But the Parti Warisan Sabah president declined to elaborate on his reasons for seeking the special motion, saying that the matter would be deliberated at the appropriate time and place, The Star reported.

May 18 will be the first Parliament sitting since the so-called backdoor Perikatan Nasional (PN) government led by Mr Muhyiddin took over from the Pakatan Harapan alliance.

The moves by Dr Mahathir and Mr Shafie have reignited a political crisis that began on Feb 24, when members of Dr Mahathir's Parti Pribumi Bersatu Malaysia - including Mr Muhyiddin - and 11 lawmakers from Parti Keadilan Rakyat (PKR) left the PH coalition, causing PH to lose its parliamentary majority.

The PH was then replaced by the PN, an alliance that Mr Muhyiddin formed with the Umno-led Barisan Nasional (BN) and Parti Islam SeMalaysia - parties that were not part of the PH pact that won the last general election in May 2018.

Despite PN taking power, PH has insisted that it, not Mr Muhyiddin or PN, has the support of the majority of MPs.

Mr Shafie has remained friendly to the PH bloc and continues to support Dr Mahathir.

The one-day Parliament will be the first test of whether either side commands a majority support of the 112 lawmakers necessary to govern the country.

Meanwhile, PKR president Anwar Ibrahim on Thursday announced that the PH alliance had named him the opposition leader, The Star reported.

Datuk Seri Anwar made the announcement in a Facebook live video, saying the coalition has informed Parliament that he would be leading them.

"The decision has been made known to all opposition parties, including a faction from Parti Pribumi Bersatu Malaysia and Parti Warisan Sabah, that I have been named the leader of the opposition once again," he said.

Mr Anwar had held the position from June 26, 2013, to March 16, 2015, during his time as MP for Permatang Pauh.

Currently an MP for Port Dickson, he replaces Umno's Datuk Seri Ismail Sabri Yaakob, who took on the role during the PH government.