There will be "winners and losers" when the new Cabinet and rankings are announced this morning, Prime Minister John Key says.
National ministers Hekia Parata, Paula Bennett and Steven Joyce and backbencher Amy Adams are expected to be given big promotions in this morning's reshuffle.
Mr Key will announce his new Cabinet and rankings at 11am.
"There are some winners and losers," Mr Key told Newstalk ZB.
"I've moved some portfolios around, moved some places around, there's some opportunities for some new people to come in, [as] we had some retirements.
"I think there's a good mix and a good line up and I like it."
Mr Key said his MPs accepted there would be changes and their were opportunities following the retirements of some portfolio holders.
"I move them not because I think they've done a bad job in their portfolio but because I want to freshen up that responsibility, someone may have come to me and said they are interested in trying something new. If everyone does the same thing the whole time, I think it has a stale feel to it and I don't want that. I want an invigorating cabinet."
Hekia Parata is tipped to get education, which promises to be a minefield portfolio with the announcement last week of charter schools to be introduced under the Act confidence and supply agreement, as well as bedding in national standards.
Steven Joyce, at present ranked 14th in Cabinet, can expect to leap to a front-bench position and the economic development and science and innovation portfolios as well as hanging on to tertiary education.
Paula Bennett is also in line for a promotion to the front bench, and is likely to keep her social development portfolio to see through promised welfare changes. While she narrowly lost her Waitakere seat at the weekend, it is not seen as a serious failure.
With the retirement of Simon Power and possible demotion in ranking of Environment Minister Nick Smith, Mr Key would have two front-bench vacancies. Anne Tolley could pick up police and corrections from Judith Collins, who is likely to get justice, previously held by Mr Power, and some aspects of commerce.
If there are no demotions from Cabinet, there are three vacancies with retirements from Mr Power, Georgina te Heuheu and Wayne Mapp.
Amy Adams, the MP for Selwyn, is expected to be promoted straight into Cabinet. She is likely to be joined by present ministers outside Cabinet Nathan Guy and Craig Foss.
That would leave three vacancies in ministerial posts outside Cabinet, along with Maurice Williamson.
Chief whip Chris Tremain is expected to get a post. Contenders for the other two posts are Dunedin-based list MP Michael Woodhouse, junior whip Jo Goodhew and Tauranga MP Simon Bridges.
Four ministers outside Cabinet have already been named in confidence and supply deals with National: Act MP John Banks as Minister for Regulatory Reform, Minister for Small Business, Associate Minister of Education and Associate Minister of Commerce; United Future leader Peter Dunne as Minister of Revenue, Associate Minister of Health and Associate Minister of Conservation; and Maori Party co-leaders Pita Sharples as Maori Affairs Minister, Associate Education, and Associate Corrections, and Tariana Turia as Minister Responsible for Whanau Ora, Minister for Disability Issues, Associate Minister of Health and Associate Minister of Housing.