Politicians from 94-year-old Mahathir's previous Pakatan Harapan (PH) coalition said they believe they are on track to form a new administration after a plan Mahathir had floated for a unity government was rejected by a rival group.

"It appears that any government coalition will have PH," Ong Kian Ming, one parliamentarian from the group told Reuters.

Mahathir, the most important figure in Malaysian politics for decades, resigned on Monday but was immediately named by the king as interim prime minister with full powers.

The king was meeting all 222 elected members of parliament over two days. Those in the meetings said they were asked to name their favored prime minister or whether they wanted fresh elections.

While some politicians have openly voiced support for Mahathir to stay in office, it was unclear whether enough of them would give him their backing at the meetings with the king to allow him to stay on.

But it was also far from certain there would be backing for another candidate such as Anwar Ibrahim, 72, an old rival of Mahathir who allied with him to win a shock election victory in 2018.

Parliamentarians allied to Anwar arrived at the palace aboard a double-decker open top bus to be greeted by cheers of "Reformasi" (reform) by supporters at the gates.

REUTERS