A small group of Liberal MPs want Malcolm Turnbull to call a party room meeting to face a leadership showdown with Peter Dutton on Thursday.
They circulated a letter on Wednesday night calling for the meeting, which would then lead to a spill of the leadership.
"I understand there's a petition. I understand that a couple of hours ago there were nine signatures on it," Liberal MP Jane Prentice told reporters on Wednesday night.
It was unclear how many MPs had actually seen and signed the letter and if any cabinet ministers were willing to shift their support from Mr Turnbull.
At least 43 signatures are required to bring on the meeting, which will be the second in a week after Mr Turnbull defeated Mr Dutton by 48 votes to 35 in a ballot on Tuesday.
A spokesman for Liberal whip Nola Marino told AAP reports of a meeting happening on Wednesday night were "completely untrue".
It's understood those pushing for the meeting want it to be held on Thursday morning.
Mr Dutton earlier on Wednesday confirmed he was still pursuing a challenge against Mr Turnbull, who chose not to accept the resignations of several ministers who voted against him.
Assistant Minister to the Prime Minister James McGrath, who was a key supporter of Mr Turnbull when he brought down Tony Abbott in 2015, resigned from his position on Wednesday night because he could not support his leader.
"Our people feel forgotten, ignored and spoken down to," Senator McGrath said in his resignation letter.
Social Services Minister Dan Tehan denied reports he had shifted support from Mr Turnbull.
"I've not resigned and I will not vote against a sitting prime minister," he said.
Health Minister Greg Hunt, who was tipped to run as Mr Dutton's deputy in Tuesday's spill, said he was not aware of the letter.
"No I haven't seen anything, I haven't signed anything," he told reporters in Parliament House on Wednesday night.
"The prime minister has my support, it has not changed."
Liberal MP Luke Howarth said he hadn't seen a petition, while another MP Warren Entsch said it was time to leave the leadership alone.
"We had a vote the other day, lets just move on," he told reporters.
Labor frontbencher Anthony Albanese said the debacle had gone on long enough.
"Whoever is the prime minister should visit the governor-general and just call an election and put them out of their misery," Mr Albanese told Sky News.
