Complaining about Prime Minister on magazine covers 'petty' - Judith Collins

National Party MP Judith Collins says she won't indulge in criticising the Prime Minister for appearing on international magazines.

Jacinda Ardern was announced as one of the people on the cover of British Vogue's September issue, which was guest-edited by the Duchess of Sussex, on Monday.

Collins was speaking to The AM Show about Simon Bridges' "part-time Prime Minister" comments made earlier in the week when the issue came up. 

"I actually think it's nice to see New Zealand people whatever persuasion on international covers," she said.

"I always remember the way the left would go absolutely hysterical with Key derangement syndrome when John Key was on a rugby thing or doing something else, it just looks petty."

Collins was happy to criticise Ardern's timing for a trip to Tokelau though, which caused Bridges' initial part-time Prime Minister comments. 

"What we're seeing is a Government that's not always turning up when it needs to and question time in Parliament is the only time that the opposition has to question the Government, and the Prime Minister could have gone during the recess and there are other times to go," she said.

She said it was clear Bridges' comments were the manifestation of frustration that Ardern isn't turning up, and ultimately she agrees with him. 

"Well I'll always agree with the leader, I've always found that to be more career-enhancing than not."

Labour Party MP Willie Jackson defended the trip, calling the part-time Prime Minister furore "nonsense".

"The reality is she's a wonderful front person for this country, she had to go over to Tokelau," he said.

"The little people count, you know, and Judith and them, they wouldn't go there because there are not enough people.

"We heard what Simon said there are more people in the street than there is in Tokelau, it's not just about the numbers Judith, it's about the people and support."