The estranged father of Barnaby Joyce's pregnant partner has emerged to declare "politics makes for strange bedfellows".

Peter Campion also told the Cairns Post he hasn't spoken to his 33-year-old daughter Vikki Campion in years after the pair had a falling out.

"Vikki's mother and I think that with Baaa-naby [sic] as dad the kid will probably be a perfect little lamb," Mr Campion said, according to a written statement cited by the Post.

"Politics sure does make for strange bedfellows."

Vikki Campion is expecting a baby with Mr Joyce. (Supplied)

Mr Campion is described by the Post as a "prolific" letter writer and a critic of the Turnbull government, which he believes has forgotten its core conservative values.

"Our future son-in-law should give himself an uppercut for failing to give one to the PM," he said, according to the Post.

A photograph of a pregnant Ms Campion, a former staffer in Mr Joyce's office, was published on the front page of The Daily Telegraph yesterday.

The Daily Telegraph published an image of a pregnant Ms Campion. (The Daily Telegraph)

It's triggered a debate about whether the image and accompanying article amounted to an invasion of privacy, or was a matter of public interest.

Deputy Prime Minister and Nationals leader Mr Joyce, 50, broke his silence yesterday in an ABC television interview during which he asked for his privacy to be respected.

"I can't quite fathom why basically a pregnant lady walking across the road deserves a front page," he said.

Mr Joyce also talked about the breakdown of his 24-year marriage to his estranged wife Natalie .

"I'll say up front that one of the greatest failures in my life was the end of my marriage," he said.

Mr Joyce and his estranged wife Natalie. (AAP)

Mrs Joyce says she and their four daughters have been hurt by the marriage breakdown.

"The situation for myself and the girls has been made worse by the fact it's been played out in public at this time," she told News Corp Australia.

Rumours of the affair and pregnancy surfaced during the by-election in Mr Joyce's New England seat in October but weren't publicly confirmed.

After winning the by-election Mr Joyce told federal parliament his marriage was over.