Barnaby Joyce has welcomed a baby boy with partner Vikki Campion, his office has confirmed to SBS News.

The child is named Sebastian and weighed 3.8 kilograms, or 8 pounds 7 ounces, at birth.

Sebastian - born at Armidale public hospital this week - is Mr Joyce's fifth child, and Ms Campion's first.

A photograph of a pregnant Ms Campion, Mr Joyce's former media adviser, was splashed on the front page of the Daily Telegraph when the story of Mr Joyce’s affair first became public.

AAP

The scandal triggered a series of events that culminated in a public spat between Mr Joyce and Prime Minister Malcolm Turnbull.

Mr Joyce eventually resigned his leadership roles to sit on the government's backbench, while the prime minister banned sex between ministers and their staff.

The couple made their first joint public comments in late February, about two weeks after their relationship was exposed. Mr Joyce told Fairfax Media he did not want his and Ms Campion's child to grow up "as some sort of public display".

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Ms Campion, reportedly uncomfortable with the limelight, refused to be photographed during the interview and made only one on-the-record comment - that her son's middle names would be in honour of her two brothers.

"Their support has meant so much. They are the only people who knew," the former journalist and media advisor said.

Mr Joyce criticised the handling of the story by Ms Campion's former employer, News Corp, which splashed her image over front pages.

He said the line of questioning about the relationship had gone from "inquiry to malice".

"The tide will turn because people will get bored of it. This should be a very simply story - a bloke whose marriage broke down is in a relationship with another person and they are having a child," he said.

"Now it seems to have gone into some sort of morality discussion. That's between me and my God."

His estranged wife Natalie's anger is understandable, Mr Joyce added, but he questioned whether the matter was anyone else's business.