Barnaby Joyce has vowed to stay on as Deputy Prime Minister amid mounting pressure for him to quit, telling his colleagues that “every political career has a time of trial”.

Mr Joyce was fighting for his political career on Tuesday as Labor sought to keep the pressure on over two jobs that were handed to his now-pregnant former staffer Vikki Campion.

Amid reports the Prime Minister had called National Party MPs to gauge their support for their leader, Mr Joyce apologised to his colleagues over the ongoing scandals.

He told the Coalition party room on Tuesday morning that “every political career has a time of trial” and he was “determined to work through this”, according to a government source.

Later, Prime Minister Malcolm Turnbull was again forced to say he had full confidence in Mr Joyce after stating his public support for the Nationals leader in Question Time on Monday.

But asked whether he was also confident his deputy had not broken the rules, Mr Turnbull said the issue was Mr Joyce’s responsibility.

“The facts of the relationship which you’re referring to are of course known to the Deputy PM, it is his responsibility to address it and comply with the standards,” he said.

“And he’s answered that, he’s addressed that in his statement today.”

Asked if the appointment of Ms Campion to the offices of the Nationals politicians Matt Canavan and Damian Drum met “the high standards expected of his ministers”, Mr Turnbull again said it was a question for the junior Coalition partner. 

Earlier, an under-the-pump Mr Joyce made a public apology outside Parliament amid reports he had acted inappropriately towards a woman at an event in 2012.

Mr Joyce strenuously denied the claim and said he reserved his legal rights following the publication of the Daily Telegraph‘s story, which alleged he had pinched a woman on the bottom.

He also denied breaking ministerial standards because he said Ms Campion was not his partner when she was moved into the office of Senator Canavan, a government minister.

The standards did not apply when she was moved to Damian Drum’s office, by which time they were in a relationship according to Mr Joyce, because Mr Drum was not a government minister.

As it did on Monday, Labor also peppered Mr Joyce with specific questions about Mr Joyce’s infrastructure portfolio in an attempt to expose him as distracted from his job.

Mr Joyce appeared more prepared than he did on Monday, when he referred to the Inland Rail in a question about Tasmanian infrastructure projects.

Later, Labor frontbencher Richard Marles tried to lighten the mood while noting New Zealand opposition leader Bill English’s resignation.

“Today the Leader of the National Party has resigned. I understand he’s a New Zealander named Bill English,” he said.

“Would the PM perhaps for the first time this week like to reflect on the legacy of a former leader of the National Party?”

Mr Turnbull replied: “I thank the Honourable Member for his question and while his motives are hardly pure in asking it, I do want to take the opportunity to reflect on Bill English’s great career as finance minister … as PM of New Zealand.”