Under-fire Barnaby Joyce is set to be acting prime minister next week as one of his Nationals MPs says he has "100 per cent support" in the party.
The deputy prime minister will take over the top job when Prime Minister Malcolm Turnbull flies to the United States to meet with President Donald Trump.
Mr Joyce is facing questions over the process which saw his now-partner Vikki Campion take up a senior advisor job in the office of Nationals whip Damien Drum while Mr Joyce was embroiled in the citizenship fiasco last year.
Mr Drum's taxpayer-funded staffing allocation was reportedly boosted to accommodate Ms Campion.
But Nationals senator Nigel Scullion angrily defended his leader on Monday.
"Fair dinkum, this is the biggest beat-up I've ever seen," the minister told reporters.
"This started off as a personal matter. There seems to be a bit of a swell - 'let's go and get rid of Barnaby'.
"I tell you what, the people who keep Barnaby in his position are National Party people and he has 100 per cent support from all of us."
Labor frontbencher Andrew Leigh said he had heard "comments" that Mr Joyce would not be acting prime minister next week.
He said the government needed to clarify the situation.
A spokesman for Mr Turnbull said Nationals office staffing is "a matter for the Nationals" and the prime minister does not sign off on staffing changes.
The spokesman said the deputy prime minister was still married when Ms Campion's appointments were made.
Asked if Mr Joyce was the best person to lead the party to the next election, Nationals senator John Williams told ABC radio on Monday: "He's certainly been a great leader and I stick by that."
But later he told ABC TV: "Let's see how all of the travel things come out and so on. I just don't know."
"I don't know if he's done anything wrong by the law of the parliament or the taxpayers and I can't judge on that."
Mr Joyce's relationship with the pregnant Ms Campion was publicly confirmed last week just two months after he told parliament his 24-year marriage was over.
Deputy Labor leader Tanya Plibersek has called on the coalition to be transparent about Ms Campion's job trajectory after the relationship with Mr Joyce became known within government circles last year.
"The only area in which there is a genuine public interest is in the area of the expenditure of taxpayers' funds," Ms Plibersek said on Sunday.
Mr Joyce received some sympathy from former prime minister Kevin Rudd.
"This is a tragic set of personal and family circumstances," Mr Rudd told the National Press Club.
"From my own experience, I know that politics is a brutal business for all of us who are in it ... and for those reasons I have not the slightest intention of contributing to the public discussion of it."
Australian Associated Press