Varawut said on Sunday that nobody from Move Forward or its seven partners has approached him to talk about joining the coalition.
The eight-party coalition will nominate Move Forward leader Pita for the PM’s post when the House and Senate convene for a joint sitting on Thursday.
The coalition still needs 64 votes – either from senators or from MPs outside the bloc – to meet the 376 votes required to make Pita Thailand’s 30th premier.
Varawut said if Chart Thai Pattana is required to strengthen the coalition, then the coalition leader should extend an invitation, not other partners.
However, he said, Chart Thai Pattana does not support Move Forward’s plan to amend Article 112 of the Criminal Code or the lese majeste law.
Asked whether Chart Thai Pattana will join the coalition that is formed if Pita fails to win the PM’s seat and if Move Forward is pushed out to form the opposition, Varawut said he could not answer on behalf of his party.
He added that his party still needs to convene a meeting to decide on its formal stance first.
Chart Thai Pattana won 10 MP seats – nine constituency and one party-list MP – in the May 14 election.