Prime Minister Malcolm Turnbull has declared his confidence in Barnaby Joyce, as National Party colleagues rallied around the embattled deputy prime minister.

Mr Turnbull had earlier failed to answer, when asked a number of times, if Mr Joyce enjoyed his support.

But, when asked in Parliament by Opposition Leader Bill Shorten if he had confidence in Mr Joyce and if he’d be acting prime minister next week, Mr Turnbull said: “Yes to both questions.”

Barnaby Joyce in Question Time today. (AAP)

Labor hit Mr Joyce with a series of questions about the appointment of his partner to National Party offices. (AAP)

That was all. No extensive defence, no ringing endorsement.

The prime minister will be out of the country for several days when he flies to Washington.

National Party MPs and senators backed Mr Joyce at their first party meeting, since news broke of the deputy PM’s affair with a former media adviser, who’s expecting his child.

However, some are questioning if Mr Joyce can survive, warning his position could become “untenable”.

Vikki Campion, who is carrying Mr Joyce's child, has become the centre of Australian political debate in the past week. (Supplied)

Any more damaging revelations, or any breach of the Ministerial Code of Conduct, could force his resignation, one source told 9NEWS.

They also questioned how he could continue to effectively push National Party policies and family values.

The Opposition today asked a series of questions about the appointment of his former adviser, Vikki Campion, to other National Party offices after she left Mr Joyce’s staff.

Mr Turnbull and Treasurer Scott Morrison distanced themselves from the appointments, saying it was a matter for the National Party Leader - Mr Joyce.

NSW Nationals Senator John Williams, who is Mr Joyce's closest ally, has said the headlines last week were a concern for the party. (AAP)

Nationals Senator Nigel Scullion has defended the party's leader today. (AAP)

And one of Mr Joyce’s closest friends and allies has conceded frustration within the National Party over the scandal.

“It’s a tough time for Barnaby, it’s a very tough time for his family,” New South Wales Senator John Williams said.

“I feel sorry for his family and no doubt Barnaby is under a lot of pressure.

“He would have had easier times in politics than he’s facing now. Only time will tell.

“There will be frustration for some, the National Party is pretty old and pretty conservative.

“I’m sure there’ll be some frustration. But we’ll see how things pan out.

“They are headlines I’d rather not see.”

Prime Minister Malcolm Turnbull and deputy Barnaby Joyce speak to reporters last week. (AAP)

Labor didn’t ask Mr Joyce any questions about his personal life in parliament, but did ask a series of questions about his portfolio.

A tactic, one insider said, designed to keep up the pressure and to keep Mr Joyce in the public eye.