Louisa Wall quits politics: Jacinda Ardern refuses to say why she would not have her in Cabinet

Departing Labour MP Louisa Wall has said she was surprised and disappointed to be told by Prime Minister Jacinda Ardern that she would never be a Cabinet minister.

Wall told Newstalk ZB's Mike Hosking that politics was more complicated than whether someone was competent or not.

"It is about the confidence somebody has in you, particularly in leadership, and unfortunately, I wasn't in the category that was provided with that privilege to sit around the Cabinet table," said Wall.

"I think there are some personalities that can work together and some that can't, at the end of the day I accepted the coach's call and then you just get on with the job."

Wall also believed that Ardern had made it clear she did not want her in caucus.

This morning, Ardern told TVNZ's Breakfast that it would not serve anyone well to discuss why she didn't want Wall to be a part of her Cabinet.

Ardern acknowledged that there were many other talented MPs that had not made it into those roles.

"That doesn't mean that they haven't played an important part in our team," said Ardern.

Prime Minister Jacinda Ardern believed her relationship with the departing Labour MP Louisa Wall was "fine". Photo / Peter Meecham

While disappointing, the absence of a Cabinet role meant Wall had time to focus on other work, Wall said.

"If I had to choose, I would choose having all the legislation I have been involved with in the past because I do really think it has benefited New Zealand and changed the lives of many New Zealanders and I couldn't have been prouder to be involved in that," said Wall.

"I didn't go into Parliament with a particular role – I went in to use my role to better New Zealanders' lives and to make a contribution."

Ardern was also focusing on the work Wall had contributed to the Labour Party over her 14 years of service.

"She's had a number of really significant bills - I'm proud to have supported all of them," said Ardern.

"They will leave a legacy and that's what I'd like to focus on at this point in her career, as well as the challenge - the next role she is taking on, which I think will also be a benefit to all of us."

Wall will deliver her valedictory speech on Thursday, before Parliament breaks for Easter.

Her resignation takes effect on May 1 - she will take a new role with the Ministry of Foreign Affairs and Trade as a Pacific ambassador for gender equality, as well as a wider role promoting LGBTQI rights.