Judith Collins has called people sharing a fitness image of potential National candidate Nuwanthie Samarakone "distasteful", adding she wished she "looked like that".
The National leader was asked about Ms Samarakone while announcing new infrastructure policy on the campaign trail today.
"It’s distasteful, actually, and I think it’s something off the potential candidate's Facebook page from some years ago.
"I don’t like that sort of behaviour and I don’t think people should acknowledge it. I understand it’s entirely a matter she has dealt with and no one else’s business," Ms Collins said.
"I think she’s an extremely fit looking person and I must say I wish I looked like that!"
Her comments come after an image from Ms Samarakone's Facebook page showing her posing in a fitness leotard was allegedly shared around by members of the National Party, according to the New Zealand Herald.
In an email obtained by the newspaper, Ms Samarakone said she felt attacked by the incident.
"I understand that some delegates have been sent a photo of me while I was competing in the fitness realm a few years ago, making utterly false and defamatory claims about what that photo represents.
"I have no tolerance for people who seek to bring down others through personal attacks, and who damage the integrity of the National Party in the process," the newspaper quoted the email as saying.
Ms Samarakone has been approached by 1 NEWS for comment.
It comes as National was thrust into another candidate selection process after the shock resignation of Auckland Central electorate MP Nikki Kaye last month, following her short rise to deputy leader under previous leader Todd Muller.
The pre-selection committee put forward two candidates, Nuwanthie Samarakone and Emma Mellow, to delegates. However, the National Party constitution sets five as the minimum number of candidates in the event there are more than five approved nominees.
Party president Peter Goodfellow said he "absolutely and categorically rejects any assertion made that the process to date was manipulated in any way".
He said with the context of Auckland Central being the "most marginal seat in the country" and with the shortened campaign time due to the retirement of Ms Kaye, "the pre-selection committee had difficult decisions to make from a wide pool of excellent candidates".
The pre-selection committee in the Auckland Central nominations voted unanimously to put forward two candidates to delegates.
"In so doing it did not strictly follow the letter of our rules. The pre-selection committee has now acknowledged that and rectified the issue.
"We now look forward to a robust selection process, where local members can determine who their next candidate will be for Auckland Central."
The party is set to decide on a candidate on August 10.