The eight-party alliance will meet on Tuesday to conclude whether the Move Forward Party (MFP) will still join them in forming the new government after other parties refused to support the coalition in a prime ministerial vote if MFP stays on.

Over the past couple of days the Pheu Thai Party (PT), which is trying to make a government after MFP failed to get its own leader elected to the post of prime minister, has asked parties for their support during the second vote planned for Thursday.

A common response is they could not agree to work with Pheu Thai if MFP, its major coalition partner, stands by its plan to amend Section 112 of the Criminal Code, also known as the lese majeste law, said Pheu Thai leader Cholnan Srikaew.

Pheu Thai intends to seek talks with all parties, except the Democrat Party, which appears unready for talks as it still is without a party leader.

"Before Pheu Thai nominates its prime ministerial candidate, the alliance will have to conclude how it can secure at least 375 votes in support of the candidate," he said.

A group of protesters on Sunday gathered outside Pheu Thai's head office while the party's executives were meeting the Palang Pracharath Party (PPRP).

Now Pheu Thai has turned to work with two military parties in disguise, Dr Cholnan must resign, protesters said.

Some protesters threw flour at Dr Cholnan and Capt Thamanat Prompow, a PPRP MP for Phayao, when they emerged from the meeting.