Barnaby Joyce will make a public statement addressing allegations of misbehaviour up to seven years ago, as his extra-marital relationship continues to make headlines.
Liberal cabinet minister Dan Tehan flagged the announcement after former Nationals leader John Anderson warned Mr Joyce his personal affairs were hurting the party and the government.
"He will be making a statement sometime today," Mr Tehan told ABC TV on Tuesday.
"No doubt he will set out his response to what's in the newspapers overnight I think that it is only right and proper to allow him to be able to refute the allegations, as I understand he will."
It's believed Mr Joyce will address media report alleging misbehaviour at official functions in 2011 and 2015 involving a number of women.
Mr Joyce's leadership of the Nationals is in the spotlight after his relationship with former staffer Vikki Campion,33, was publicly exposed last week and questions began to be asked about her job appointments.
Ms Campion moved from the Nationals leader's office earlier last year to work for minister Matt Canavan, after the relationship became known, and then on the office of the Nationals whip Damian Drum.
"There were rumours around the parliament that something was going on, but certainly at the time that Vikki came to work in my office, my understanding was that it was no longer an ongoing affair," Mr Drum told ABC radio.
Malcolm Turnbull told federal parliament on Monday the "distribution of those staff members between Nationals offices is a matter for the National Party".
Mr Joyce had not breached ministerial standards in regard to the employment of family and partners because Ms Campion was not the deputy prime minister's "partner" at the time of her appointments, a spokesman said.
The statement of ministerial standards says close relatives and partners cannot be employed by any members of government "without the prime minister's express approval" and must not be employed in other executive government offices.
The Daily Telegraph reported on Tuesday Mr Turnbull was told by Mr Joyce in August the affair was over.
Ms Campion, who is pregnant with Mr Joyce's fifth child, reportedly due in April, left Mr Drum's office late last year.
In December, Mr Joyce told parliament his 24-year marriage to Natalie, with whom he has four daughters had broken down.
Former Nationals leader John Anderson told The Australian Mr Joyce, who will become Acting Prime Minister next week while Mr Turnbull is in the US, must take responsibility for the political damage the revelations have caused to the party.
"The issue is creating a problem within the National Party and for the government and must be resolved," he said, without saying directly what should be done.
Asked if voters would agree Ms Campion wasn't Mr Joyce's partner at the time of her appointments, Treasurer Scott Morrison said it was difficult to untangle.
"He can't have two partners at the same time and he was obviously still married," he told ABC TV on Monday night.
Labor is demanding Mr Joyce be "utterly complete" in his statement.
"It is very clear that Barnaby Joyce and, frankly, Malcolm Turnbull need to make a full account of their knowledge and their actions in all these matters," shadow treasurer Chris Bowen told ABC radio.
Mr Joyce would need to fully deny the latest allegations because his position was becoming "increasingly untenable".
"Any incident in which something has happened particularly to a woman which has made her feel uncomfortable I think is serious," Mr Bowen said.
Cabinet minister Mathias Cormann insisted Mr Joyce's position was a matter for the National Party.
"But of course we all support Barnaby as a valued friend and colleague," he said.
Australian Associated Press
