Federal Labor will continue to question whether Barnaby Joyce's girlfriend was given favourable treatment, despite Cabinet ministers insisting no rules have been broken.

Key points: Deputy Labor leader Tanya Plibersek is calling for more transparency over Vikki Campion's employment circumstances

Deputy Labor leader Tanya Plibersek is calling for more transparency over Vikki Campion's employment circumstances Ms Plibersek's questions come a day after PM Turnbull said no taxpayer money was wasted in moving Ms Campion out of her job

Ms Plibersek's questions come a day after PM Turnbull said no taxpayer money was wasted in moving Ms Campion out of her job Nationals MP Michelle Landry has warned the ALP not to "throw stones"

Mr Joyce began an affair with his media adviser Vikki Campion — who is now pregnant with his child — and was advised last year that it was inappropriate for her to continue working with him.

She was then moved into a newly created and unadvertised position in Nationals Minister Matt Canavan's office and subsequently transferred into Nationals MP Damian Drum's office.

Prime Minister Malcolm Turnbull, Senator Canavan, Mr Joyce and other senior Cabinet ministers insist the appointment was appropriate and all recruitment policies were followed.

But deputy Labor leader Tanya Plibersek is not convinced.

She said while Labor will not be commenting on Mr Joyce's personal life, there are legitimate questions to ask about her employment circumstances.

"The only area in which there is a genuine public interest is in the area of expenditure of taxpayer funds," Ms Plibersek said.

"There have been questions over the last few days about jobs that have been created for Vikki Campion and the expenditure of taxpayer funds on travel."

The ABC has been told Mr Joyce returned a small amount of taxpayer money after he used a rental car to return to a holiday with Ms Campion.

"The thing that is to be asked in this situation is was this job necessary, was there work to be done at this skill level, what was the case made for having to hire someone additional into those offices?" Ms Plibersek said.

Her questions come a day after Mr Turnbull said no taxpayer money was wasted when the Federal Government moved Ms Campion out of her job.

The ABC asked the Prime Minister's office whether Ms Campion was paid more as a result of the move, but questions were referred to Mr Joyce's office.

Mr Joyce's office said Ms Campion had been employed as a media adviser but would not say whether she was paid more once she moved to Mr Canavan's office.

Mr Canavan's office said Ms Campion was hired for a specific role, but would not reveal whether her salary increased.

Mr Drum would not comment on her recruitment on Sunday.

Labor should be wary of 'glass houses'

Crossbench senator Derryn Hinch said someone needed to provide a full and detailed explanation of how she got the job.

One Nation leader Pauline Hanson also said she was not satisfied with the Government's explanation of the transfers.

The senator said she did not want to comment on Mr Joyce's private life, but said the issue had developed beyond that now it involved recruitment and potential use of taxpayer funds.

Ms Plibersek's declaration of intent also drew a few warning shots from Coalition MPs, who gathered in Canberra for a Family Day lunch at The Lodge.

When asked about Ms Plibersek's comments, Foreign Minister Julie Bishop said, "people in glass houses".

Nationals MP Michelle Landry said she was confident all recruitment rules had been followed and gave a similar warning.

"You shouldn't throw stones when you have glass walls because we could start doing a bit of digging there as well," Ms Landry said.

Nationals MP Michael McCormack said he was confident Mr Joyce would remain leader of the party at the next election.

"The fact that Vikki has moved from his office to Matt Canavan's office … there was a position for her and it was filled correctly," Mr McCormack said.