The Prime Minister has delivered a scathing rebuke of the Deputy Prime Minister as he revealed changes to the ministerial code of conduct.
Mr Turnbull said while ministers were entitled to personal privacy they also occupied "positions of great responsibility and public trust".
"Ministers should be very conscious that their spouses and children sacrifice a great deal so they can carry on their political career and their families deserve honour and respect," he said.
The prime minister said sexual relationships with staff was "very bad workplace practice".
"You know what attitudes in the corporate world and elsewhere are to this kind of thing. It is about time that this change was made. Probably should have been made a long time ago," he said.
Asked why his deputy had not been urged to resign, Mr Turnbull said Mr Joyce had to "consider his own position" as he undertook leave next week.
Senate calls for Joyce to resign
The Senate has added insult to injury for Barnaby Joyce, calling on the embattled deputy prime minister to quit.
Greens leader Richard Di Natale moved a motion calling on Mr Joyce to resign for "clearly breaching the standards required of ministers" and if he does not resign, urging the National Party to sack him.
The motion passed the Senate on Thursday with the support of Labor, the two Nick Xenophon Team senators and independent Derryn Hinch.
Labor and the Greens have zeroed in on the under-fire Nationals leader over his acceptance of a rent-free apartment offered to him by businessman Greg Maguire.
He is also being grilled over whether any rules have been broken in regard to jobs provided to his former staffer and now partner Vikki Campion.
Mr Joyce will take a week of personal leave next week and will not step up as acting prime minister while Malcolm Turnbull is visiting the United States.
The last-minute announcement comes amid intense media scrutiny and attacks from the federal opposition over his handling of an affair with a former staffer.
"The deputy prime minister will be taking leave from Monday 19 February to Sunday 25 February, and accordingly will not be able to be acting prime minister while I'm overseas," Mr Turnbull told parliament at the start of Question Time on Thursday.
With foreign minister Julie Bishop also overseas, the government's Senate leader Mathias Cormann will act as prime minister next week.
Labor leader Bill Shorten said the effort to shield Mr Joyce from further scrutiny was evidence he could no longer do his job.
Leave comes as Labor calls for sacking over 'gifted' house
The opposition is urging Prime Minister Malcolm Turnbull to sack his deputy over a "gift" of free accommodation, despite Mr Joyce insisting he never breached ministerial rules.
The opposition tried but failed to pass a motion calling for the sacking on Thursday morning, with shadow attorney-general Mark Dreyfus accusing Mr Joyce of the "clearest possible breach" of the ministerial code of conduct, which says ministers should not attempt to encourage personal gifts.
Mr Joyce concedes he was given free access to a property in Armidale by wealthy businessman and political donor Greg Maguire, who he describes as a "mate", but denies any wrongdoing.
He moved into the house with his former staffer Vikki Campion, who is now his partner and is expecting a child. The couple's affair and the breakdown of Mr Joyce's marriage was revealed in national media last week.
Mr Joyce has acknowledged the property in the "gifts" section of his pecuniary interest register, in an update he submitted after his by-election victory in New England last December. The listing does not put a value on the gift and simply reads: “Post election residual of six-month tenancy on Armidale premises".
The Nationals leader said the offer came after he was ejected from parliament by the High Court, so he was not a minister at the time. Mr Joyce also said the gift was offered, not solicited, so would not be covered by the code.
"[Mr Maguire] basically said mates don't pay for things when they're helping other mates out, and that's precisely what happened," Mr Joyce told parliament.
"Mr Maguire approached me, he made an offer," he said.
But two News Corp journalists - Sharri Markson and Rick Morton - claim Mr Maguire told them Mr Joyce was the one who initiated the conversation, contacting him to ask for a place to stay.
Poll shows New England voters split on Joyce affair
Voters in Barnaby Joyce’s electorate of New England are split almost 50-50 on whether the Nationals leader should resign in the wake of the scandal, according to a new opinion poll commissioned by Fairfax Media.
The poll found 45.3 percent of voters in the northern NSW seat wanted Mr Joyce to remain as party leader and deputy prime minister.
Another 26.7 percent said he should resign from his leadership positions and move to the backbench, while a further 20.5 percent said he should quit parliament completely. 7.5 percent were undecided.
Arriving at Parliament House on Thursday, a defiant Barnaby Joyce said he was confident he would survive as Nationals leader.
"I’ve got the support of my party room," Mr Joyce told reporters as he entered the building. "We’re back into the business, working hard, doing what we’re supposed to."
Along with the questions over the free Armidale rental, Labor is pushing the government to release details of any taxpayer-funded trips taken by deputy prime minister Barnaby Joyce and Vikki Campion while she was working as a Nationals staffer.
On Wednesday, Labor senator Kimberley Kitching tabled a notice of motion calling for the details of Mr Joyce and Ms Campion's “special purpose travel” and any international flights.
Opposition leader Bill Shorten said Mr Joyce's position had become "untenable", echoing calls from other Labor MPs for the deputy PM to resign.
"Australians are not interested in Barnaby Joyce's private life, that's his," Mr Shorten said. "But there are conflicts of interest coming out daily which are being revealed. The prime minister has a ministerial code of conduct which, if he doesnt uphold, is not worth the paper it's written on."
The questioning is likely to continue in Question Time on Thursday afternoon. It is the last sitting day of parliament before Mr Joyce is due to take over as acting prime minister, while Malcolm Turnbull is abroad in the United States next week.
Mr Joyce has been under intense political pressure and media scrutiny since his affair with now-pregnant Ms Campion was revealed.
Nationals back Joyce to keep leadership, for now
The pressure on Mr Joyce has forced his colleagues to declare their support for his ongoing leadership.
A number of his fellow 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".
Their defences came 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.
"He'll probably need the advice and someone needs to tell him where the party stands at this stage," he told reporters on Wednesday morning.
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.
Joyce denies jobs for Vikki Campion breached code of conduct
The ministerial code of conduct 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."
In the Senate chamber on Thursday afternoon, Senator Canavan confirmed Ms Campion was the only person interviewed for the role in his office.
"I can confirm that Ms Campion was interviewed for the role in my office on a number of occasions, Senator Canavan said.
"And as often is the case with such appointments, Ms Campion was the only person interviewed for the role because she had the skills and experience and she was well known of course, given her previous experience for the Nationals party in this place."