National Party leader Todd Muller, who defeated incumbent Simon Bridges on Friday, is announcing few changes in his reshuffled front bench.

Senior National MP Amy Adams has backtracked on her retirement plans after a change of leadership last week and is ranked third in caucus following a minor reshuffle.

New National Party leader Todd Muller has given Adams a new portfolio, Covid-19 recovery, but for the most part has left caucus roles largely unchanged.

Simon Bridges, who lost the leadership to Muller in a caucus vote on Friday, remains unranked for now, having asked for "time to reflect on his future".

The New Zealand Herald reported that Bridges turned down the role of Justice spokesperson and asked for Foreign Affairs. The request was rejected, the Herald said.

Muller said there would be a place for Bridges in his senior leadership team should he decide to stay in politics.

He said he was particularly pleased Adams had agreed to stay on - she announced in June last year that she was retiring at the election and denied it was because of the leadership of Bridges and deputy Paula Bennett.

Muller had already revealed he had given himself the small business portfolio that had belonged to Todd McClay. He is also taking national security.

His deputy Nikki Kaye keeps her education and sport and recreation portfolios.

Kaye this morning refused to say on Morning Report which portfolios she would be handling. She would only say that she was happy with her new responsibilities.

Judith Collins' housing and urban development portfolio has gone to rising star Nicola Willis who actively worked on Muller's campaign.

Collins remains in her fourth spot ranking in the caucus but takes on economic and regional development as well as shadow attorney-general and Pike River.

Paul Goldsmith and Gerry Brownlee keep finance and foreign affairs respectively, and Brownlee will continue as shadow leader of the house.

RNZ has been told senior MP Gerry Brownlee was top of Muller's list to be the new campaign chair to replace former deputy Paula Bennett.

Michael Woodhouse - a Bridges loyalist - has held onto health and Louise Upston keeps social development.

Mark Mitchell, another Bridges' supporter, has not been punished by the new leadership either, keeping justice and defence.

Bridges' numbers man and closest ally Todd McClay holds onto trade and tourism but loses economic development to Collins.

One of Muller's biggest supporters Chris Bishop keeps infrastructure and transport but has not had a significant jump in the caucus rankings.

Bennett holds onto drug reform and women.

There has been barely any change to the lower end of the rankings.

The biggest loser looks to be long-time MP and deputy speaker Anne Tolley, who has a very low caucus ranking, making it difficult to see her returning if the party vote does not considerably improve.

Tolley had given up her electorate seat to run as a list-only candidate at this year's election.

National MPs retiring at the election are David Carter, Nicky Wagner, Nathan Guy, Maggie Barry, Sarah Dowie and Alastair Scott.

It's understood Muller spent last night contacting MPs to tell them their fate, keen to put the matter to rest before tomorrow's regular caucus meeting.