A senior Nationals MP has backed Barnaby Joyce's leadership as Labor continues to pressure the federal government over issues related to his extra-marital affair.
Asked if the deputy prime minister was the best person to lead the Nationals to the next federal election, Senator John Williams said: "He's certainly been a great leader and I stick by that."
Mr Joyce's relationship with his now pregnant former staffer Vikki Campion, 33, was publicly confirmed last week just two months after he told parliament his 24-year marriage was over.
Senator Williams lamented the recent headlines about his leader's personal situation.
"I wish it didn't happen," he told ABC radio on Monday.
"Barnaby, he'll be suffering under this too, he's under a lot of pressure and he's been a good mate for many years. I wish I could turn the clock back, but I can't."
Senator Williams said it was also a very sad situation for Mr Joyce's estranged wife Natalie and his four daughters.
Questions are now being asked about Ms Campion's employment during her time with the federal Nationals, after the media advisor last year moved from Mr Joyce's office to the office of minister Matt Canavan and later to the office of Nationals whip Damian Drum.
Deputy Labor leader Tanya Plibersek has called on the coalition to be transparent about Ms Campion's job trajectory after her 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.
"There have been questions over the last couple of days about jobs that have been created for Vikki Campion, the expenditure of taxpayer funds on travel.
"I think those are areas where the prime minister and the deputy prime minister ought to be fully transparent."
The government maintains nothing untoward happened, pointing to Ms Campion's strong jobs skills.
Meanwhile, Nine Network has cited unnamed government sources as saying Mr Joyce's position is "untenable" and that he "should go".
Ms Campion, a former journalist, was initially a media advisor for Mr Joyce before going to work for Senator Canavan.
When Senator Canavan stepped down from the front bench in July following question over his citizenship, she when to work for Mr Drum.
Australian Associated Press