Barnaby Joyce is adamant he will survive as federal Nationals leader despite a public call for his resignation from a party room colleague and a sexual harassment complaint.
Victorian MP Andrew Broad became the first Nationals federal MP to call for the leader to quit, vowing to bring the matter to a head at a party room meeting in Canberra on Monday.
Assistant Families Minister David Gillespie could put his hand up to replace Mr Joyce amid reports the NSW Nationals MP has indicated to colleagues his willingness to run if he resigns.
Fellow NSW MP and Veterans Affairs Minister Michael McCormack, who recently gave an interview in which he dodged multiple questions about his support for Mr Joyce, is also considered a possible contender.
The scandal has caused headaches for the coalition government, which had to call in Liberal minister Mathias Cormann to act as prime minister while Malcolm Turnbull is in the US after Mr Joyce took personal leave.
READ MORE: Turnbull declines to support Barnaby from DC
Speaking in Washington DC, Mr Turnbull declined to publicly back Mr Joyce, saying "leadership of the National party is a matter for the National party".
His colleague Christopher Pyne also wouldn't comment on the Nationals leadership, but told the Nine Network: "I support him as a cabinet colleague, of course I do and as a friend."
Mr Broad's intervention came before the party confirmed late on Thursday it had received a formal sexual harassment complaint against Mr Joyce.
Federal director Ben Hindmarsh said the complaint would be taken seriously, treated with strict confidentiality and given due process.
A spokesman for Mr Joyce said he had been "made indirectly aware" of allegation and described it as "spurious and defamatory".
Despite mounting pressure, Mr Joyce is digging in after it was revealed earlier this month he had an affair with a former staffer who's now pregnant with his child.
He told Fairfax Media he was confident he would still be leader after Monday's party meeting.
"Andrew Broad has expressed these sentiments before," Mr Joyce said.
"The proper venue for the discussion of these issues is within the party room, which we will do on Monday."
Mr Broad or another MP could move a motion calling for a leadership spill or a motion calling on Mr Joyce to step down.
"At this point in time he should take a step back and stand down and be on the back bench," Mr Broad told ABC radio.
"(He can take) some time to regroup and he may come back to make a further contribution."
Labor frontbencher Anthony Albanese again called for Mr Joyce to resign, criticising his decision to do media interviews during a week of leave.
"The deputy prime minister's first job is to deputise for the prime minister. He himself has admitted this week he can't do that job," he said.
"He just should go."
Australian Associated Press