Key points:
- Delegation of Nationals colleagues to meet with Mr Joyce to discuss his future
- Joyce confirms ex-staffer Vikki Campion is now his “partner” but denies breaching ministerial rules
- Apologises to estranged wife, children and Ms Campion for “all the hurt”
Labor is demanding to see details of tax-payer funded flights Nationals leader Barnaby Joyce and his staffer-turned partner Vikki Campion took in 2017.
Concerns have been raised about the potential misuse of taxpayer funds while now-pregnant Ms Campion worked in various ministerial and MP offices.
Labor senator Kimberley Kitching on Wednesday tabled a notice of motion calling for the details of Mr Joyce and Ms Campion's "special purpose travel" and any international flights.
Mr Joyce has denied breaching the ministerial code of conduct and said Ms Campion was not his partner when she worked in his and Matt Canavan's office, while Damian Drum was not a minister when she transferred to his office.
Nationals deputy leader Bridget McKenzie has pledged her "110 per cent" support for Mr Joyce as speculation over his grip on the leadership continues.
"I back Barnaby Joyce 110 per cent, like everyone that actually wants to make a difference in the regions should," Senator McKenzie told reporters on Wednesday afternoon.
"I'll give you my solid, rolled-gold guarantee here that come tomorrow, come Friday Barnaby Joyce will be leading the National party."
The strong defence comes after Nationals MP Ken O'Dowd said a delegation of his colleagues planned to visit Mr Joyce to "tell him where the party stands" on his leadership.
Mr Joyce faces growing pressure to resign over a recently exposed affair with his former media advisor.
Mr O'Dowd said he hoped to have the matter "resolved today or tomorrow", speaking outside Parliament House on Wednesday morning.
"He'll probably need the advice and someone needs to tell him where the party stands at this stage," he said.
Mr O'Dowd said there were plenty of capable candidates if the scandal triggered a leadership spill.
He has previously suggested he may put his hand up for the leadership himself.
“We would find a good leader, I feel sure about that,” he said.
The MP said he had not heard from Mr Joyce in the past 24 hours.
Allies jump to Joyce's defence
Forcing the Nationals leader to step down would require the majority of the 21-member party room.
But several Nationals have jumped to their leader's defence. MP David Littleproud said "of course" Mr Joyce retained the support of the majority of members. "He's done an amazing job for regional and rural Australia," he said.
Nationals whip Michelle Landry said she believed Mr Joyce still had the numbers and would "remain our leader".
Senior Nationals MP and Veterans Affairs Minister Michael McCormack, who has missed out twice on becoming deputy leader, said he had not had any conversations with colleagues about replacing Mr Joyce.
Former Nationals leader Warren Truss weighed in on the leadership doubts on the ABC's 7:30 program on Tuesday. He said Mr Joyce's handle on the leadership had been "diminished" and warned he would need to "demonstrate" he could still do the job.
"These types of interludes are unhelpful and need to be resolved quickly," Mr Truss said.
Labor used Question Time in parliament on Tuesday to ask Prime Minister Malcolm Turnbull whether he remained confident in his deputy. "Yes," Mr Turnbull replied.
The Nationals party president Larry Anthony has arrived in Canberra for meetings on the Joyce matter. He told reporters it was a "difficult time".
"But the Nationals party always works through these issues," Mr Anthony said.
A defiant Barnaby Joyce gave a brief statement to the media outside Parliament House on Tuesday morning. He did not take any questions, but gave no indication he was considering resigning over the growing scandal.
He apologised to his estranged wife and his four daughters "for all the hurt" caused by the fallout from his recently exposed affair with his former media advisor Vikki Campion who is now pregnant with their child.
He also apologised to Ms Campion who he conceded was now his "partner".
Labor MP Chris Bowen said Mr Joyce's position was coming increasingly "untenable", while the Greens party are calling for him to resign his ministerial responsibilities.
No breach of ministerial rules: Joyce
The says partners and close relatives of ministers are not allowed to be given jobs within the minister's office, or with other members of the executive, without the express permission of the prime minister.
Ms Campion was moved from Mr Joyce's office into the employment of Nationals colleague Matt Canavan and then to the office of Damien Drum.
Mr Turnbull's office said the prime minister had never needed to grant permission because Ms Campion was not Mr Joyce's "partner" at the time.
Speaking with reporters on Tuesday morning, Mr Joyce denied breaching the code.
"It is without a shadow of a doubt that Vikki Campion is my partner now," Mr Joyce said.
"But 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."
Bishop still expecting Joyce to play PM next week
Barnaby Joyce is due to serve as acting prime minister next week, while Malcolm Turnbull visits the United States and meets with president Donald Trump.
If Mr Joyce is not available, the role would normally fall to foreign minister Julie Bishop, who is currently visiting Kuwait and plans to still be overseas next week.
Ms Bishop said the prime minister had not asked her to make herself available, and said she expected Mr Joyce to step up as usual.
"I'm over in Kuwait with back-to-back meetings from very early in the morning to late at night ... so it's not a matter that I'm focusing on," she told ABC Radio on Wednesday.
Ms Bishop said she planned to be overseas next week but said "if circumstances change then, of course, I would change plans".
Barnaby Joyce and Vikki Campion timeline
2016
May - Vikki Campion assists Barnaby Joyce's election campaign as media adviser, having previously worked with NSW government ministers and News Corp
August - Campion joins Joyce's staff. She splits with fiance John Bergin, three months before they were due to wed. Friendship develops between Joyce and Campion
December - Chief of staff Di Hallam reportedly seeks Joyce's approval to have Campion transferred out of office. Hallam later quits to take up departmental role
2017
February - Campion is photographed in a Sydney bar with Joyce
April - Barnaby's wife Natalie reportedly confronts Campion in Tamworth. Campion goes to minister Matt Canavan office as adviser. Natalie and Barnaby seek to make marriage work
May - At NSW Nationals conference in Broken Hill colleagues describe Joyce as "a mess"
June - Natalie and Barnaby show up together at Canberra press gallery midwinter ball
July - Campion leaves Canavan office after he quits frontbench over citizenship. She temporarily goes back to Joyce's office
August - Campion moves to Damian Drum's office in a social media adviser position specially created for her. He already has a media adviser. Prime Minister Malcolm Turnbull is reportedly reassured by Joyce the relationship with Campion is over. Drum says he was told the same thing. Former Joyce chief of staff Di Hallam takes up a senior position with the Inland Rail project
September - Natalie reportedly asks family friend, Catholic priest Father Frank Brennan, to counsel Joyce. Campion is seen managing Joyce media events at federal Nationals conference in Canberra
October - Campion reportedly takes stress leave. Writ issued for New England by-election after Joyce quits over dual citizenship
November - Natalie holidays in Bali with a daughter. Man in a pub in Inverell angers Joyce during election campaign by reportedly saying: "Say hello to your mistress"
December - Joyce wins by-election. Joyce tells parliament during same-sex marriage debate he is separated. Campion's redundancy package is approved. They move into an Armidale property provided rent-free by businessman Greg Maguire
2018
January - Joyce and Campion holiday in north Queensland and NSW north coast
February - Joyce tells reporters Campion is now his partner. But denies she was his partner when she worked in Canavan's office
Mid-April - Joyce-Campion baby is due
(Source: Based on media reports and official statements.)
- with AAP