Natalie Joyce, the wife of Nationals MP Barnaby Joyce, has spoken for the first time since the former deputy prime minister's affair with his staffer became public.

Ms Joyce told Women's Weekly she had to resist "throwing a brick at the TV" as she watched Mr Joyce's interview with Channel Seven earlier this month, for which he was reportedly paid $150,000.

She questioned whether the money should have been paid into a trust fund for Mr Joyce and staffer Vikki Campion's son.

"It begs the question, if Barney agreed to be a part of it, how could he allow his four girls to be overlooked? In saying that, I wouldn't want a cent of that money," she said.

The Women's Weekly reported the interview was unpaid, and Ms Joyce accepted it before the controversial Channel Seven interview as an opportunity to be heard.

"I'm doing this so the girls feel empowered, and know their mum stood up and defended our fine name," she said, referring to their four daughters.

Ms Joyce also expressed concern for her former partner's mental health.

At the weekend, Mr Joyce told media his younger brother Tim had died of cancer.

Mr Joyce is currently on leave. His office has been contacted for comment.