Malaysia's Prime Minister Designate and former interior minister Muhyiddin Yassin waves to reporters outside his residence in Kuala Lumpur, Malaysia, February 29, 2020 – PHOTO: REUTERS

The decision could again reshape politics in the Southeast Asian country less than two years after an alliance of Mahathir, and old rival Anwar Ibrahim, 72, swept out the former ruling party that had been tarnished by corruption scandals.

That former ruling party of six decades, the United Malays National Organisation (UMNO), was among those that had rallied in support of Muhyiddin, along with the Islamist party PAS.

Although Mahathir and Anwar announced on Saturday that they had joined hands again, the palace said in a statement the king made his decision on the basis that Muhyiddin possibly had the support of a majority in parliament.

"His majesty has decreed that the process of appointing a prime minister cannot be delayed," it added. "This is the best decision for all."

Muhyiddin, 72, will be sworn in on Sunday.

"I only ask for all Malaysians to accept the decision announced by the national palace," Muhyiddin told reporters at his home.

Muhyiddin's position could still depend on being able to win a confidence vote in parliament.

The top trending hashtag on Twitter in Malaysia was #NotMyPM.

There was no immediate reaction from Mahathir, who has been interim prime minister since he resigned, or Anwar.

Salahuddin Ayub, a lawmaker from Mahathir and Anwar's political coalition, said they would gather evidence to prove they would be able to form a majority in parliament.

UMNO springs back

Muhyiddin is from Mahathir's Bersatu party, but had shown himself ready to work with UMNO - from which he had been sacked in 2015 after questioning former prime minister Najib Razak's handling of the 1MDB corruption scandal.

Najib is now on trial on corruption charges.

UMNO's fortunes have risen since its 2018 defeat, with Mahathir and Anwar's Pakatan coalition losing five by-elections in the face of criticism from some Malay voters that it should do more to favour the biggest ethnic group in the country of 32 million.

UMNO, which Mahathir led from 1981 to 2003 during a previous stint as prime minister, supports Malay nationalism.

The latest crisis was sparked by a tussle for power between Mahathir and Anwar that has shaped Malaysian politics for two decades. Mahathir had promised to hand power to Anwar after the 2018 election, but no date had been set.

After resigning last Monday, Mahathir had sought to form a national unity government that would have given him greater powers, but he won little public support while Anwar rejected the plan and put himself forward for the premiership.

Anwar was Mahathir's deputy and a rising political star when Mahathir was prime minister the first time, but they fell out over how to tackle the Asian financial crisis.

Anwar was arrested and jailed in the late 1990s for sodomy and corruption, charges he says were politically motivated.

As well as personal relationships, politics in Malaysia is shaped by a tangle of ethnic, religious and regional interests. Malaysia is more than half ethnic Malay, but has large ethnic Chinese, Indian and other minorities. Reuters