Former National Party leader Todd Muller has revealed he will run at the next election despite announcing in June he would retire.

It comes as the Bay of Plenty MP has been named as an unranked member of the Chris Luxon-led National Party caucus. Muller holds the oceans and fisheries and internal affairs portfolios.

Muller said he was comfortable with not being given a ranking.

"I genuinely have no concerns at all, as there is so much work to do, not only to prosecuting this Government but continuing to build a clear vision of what the party would do differently."

Muller also said ultimately he would do what was best for the National Party and his constituents.

"I'm excited and certainly feel reinvigorated and I have signalled to the Bay of Plenty electorate chairperson Mary Webster that I will put my name forward to stand again at the 2023 election."

Muller said he was "delighted and excited" with the portfolios he has been given, and to be able to continue to contribute to party successes.

"Oceans and fisheries is a pertinent portfolio for this country, especially this electorate [Bay of Plenty]," he said.

Asked about the party caucus, Muller said: "I think it's a great line-up and you get a real sense of a National Party caucus chosen very much on performance which is a good thing.

People want to see a shadow cabinet of MPs who can run the future government."

In June, Muller announced he planned to retire at the next election after nine years as the MP for the Bay of Plenty.

Muller was first elected to Parliament in 2014 as the MP for Bay of Plenty, a seat he won again in 2017.

On May 22 last year, an election year, Muller ousted Tauranga MP Simon Bridges to become leader of the National Party.

Just 53 days later, Muller made the shock announcement he was stepping down from the role for health reasons. Since then he has opened up about his mental health battles, particularly with anxiety and panic attacks.

Bridges is ranked third in the National Party caucus and holds the finance and infrastructure portfolios.

Meanwhile, Rotorua MP Todd McClay has fallen from number six to unranked in the new caucus. He has the trade portfolio and tourism.

One of the biggest losers of the reshuffle is former leader Judith Collins, demoted to 19th. But she still stays in the shadow cabinet and has the research, science and innovation portfolio.

Luxon decided to part with the tradition of giving the entire caucus - except new and departing MPs - a numbered ranking. Instead, he's given rankings to the first 20 MPs and left the rest unranked.

'Ultimate team sport'

Speaking at a press conference after revealing the reshuffle this afternoon, Luxon described politics as the "ultimate team sport".

He said his line-up was based on performance, as well as matching people to their experience and skills.

Luxon said every MP had a significant role to play, and he hadn't ranked those below the shadow Cabinet because it was irrelevant, and performance mattered more than ranking.

The new party leader said he'd spoken to every MP himself but had not talked to previous leaders Sir John Key or Bill English or Steven Joyce to get their opinions on MPs' strengths and weaknesses.

He said another former party leader, Muller, had re-entered the caucus. Luxon said it was a decision for Muller to make whether to stand again in the next election.

"I know he wants to come back and be part of our team."

Luxon this afternoon said he watched the MPs closely for the past year and saw where their strengths and weaknesses lay.

He said he had watched low-ranked MPs perform very well against their counterparts in that area.