Barnaby Joyce has apologised to his estranged wife, daughters, pregnant partner, coalition MPs and voters but the deputy prime minister is determined to get through his "time of trial".
Malcolm Turnbull expressed confidence in the Nationals leader, who denied breaching the ministerial code of conduct over the employment of his girlfriend Vikki Campion in two political jobs.
"I would like to say to (my wife) Natalie how deeply sorry I am for all the hurt this has caused. To my girls, how deeply sorry I am for all the hurt it has caused them," My Joyce told reporters outside federal parliament on Tuesday.
"To Vikki Campion, how deeply sorry I am that she has been dragged into this."
Later in a written statement, Mr Joyce said his marriage was under pressure for some time.
"Natalie and I tried to make it work again in April last year but it subsequently came to an end," he said.
"This has been a searing personal experience for Natalie, our daughters and for Vikki - criticise me if you wish but please have some regard for them."
He also apologised to voters in his New England electorate for "this personal issue" going public.
"Every political career has a time of trial," he told a coalition party room meeting.
Ms Campion began working in Mr Joyce's ministerial office in August 2016.
"A friendship subsequently developed and that became, over time, more," he said.
But he denied breaching the ministerial code of conduct, which says frontbenchers cannot employ close relatives or partners or get them work in other ministerial offices "without the prime minister's express approval".
Ms Campion moved from Mr Joyce's office in April to work for Nationals MP and cabinet minister Matt Canavan, and then to the office of then-Nationals whip Damian Drum, after Senator Canavan stepped down following questions over his citizenship.
"When she worked in my office, she was not my partner. When she worked in Matt Canavan's office, she was not my partner. And Damian Drum was not a minister," Mr Joyce said.
Senator Canavan told parliament the job was organised in consultation between his office and the deputy prime minister's office.
"I had no knowledge of the relationship between Mr Joyce and Ms Campion at the time," said Senator Canavan - who was Mr Joyce's chief of staff before entering parliament.
"And as he (Mr Joyce) has said in his statement this morning, she was not his partner at the time."
Mr Turnbull was grilled in parliament about the definition of the word "partner" in the code of conduct, and he replied with the definition used by Centrelink.
"It is (Mr Joyce's) responsibility to address it and comply with the standards. And he's answered that, he's addressed that in his statement today," the prime minister said.
The Greens called on Mr Joyce to quit, while Senator Cory Bernardi said people had two reasonable expectations for politics.
"One is the Australian people will not get screwed by their government and, two, ministers will not screw their staff," Senator Bernardi said.
The Daily Telegraph reported on Tuesday Mr Turnbull told MPs in August he'd been reassured by Mr Joyce the "affair was over".
In December, Mr Joyce told parliament his 24-year marriage to Natalie Joyce had broken down.
His child with Ms Campion is due in mid-April.
Mr Joyce also denied allegations, which have also been circulating on social media, he misbehaved at an awards ceremony for rural women in 2011.
© AAP 2018