Defence Minister Marise Payne is out of hospital and fighting back at Liberal party colleagues who've been attempting to undermine her.

Senator Payne has been on sick leave with a severe abdominal infection that required surgery.

But there have been rumours spread that she had a nervous breakdown and was too afraid of appearing on television because she was too fat.

"What I think is the sort of people who engage in that sort of behaviour should probably really look in the mirror,'' Senator Payne told News Corp's Sunday mastheads in her first interview since her illness.

Senator Payne said she was now looking forward getting back to work.

Last week, her Canberra housemate and Defence Industry Minister Christopher Pyne angrily denied he was undermining his colleague.

Mr Pyne told Fairfax Media in Paris: "Whoever would be saying such a thing is a liar".

Former NSW premier Barry O'Farrell tweeted his support for Senator Payne, saying "all because they can't attack@MarisePayne's intellect of competence #nameless cowards."