Prime Minister John Key has reinstated Judith Collins to Cabinet as the Minister for Corrections and for Police.
But Mr Key said it was not a reflection of the performance of current Corrections Minister Sam Lotu-Iiga, rather that he wanted those portfolios to be held by the same minister, and that they were a good fit for Ms Collins.
"I am pleased to welcome Judith Collins back to Cabinet," he said.
"Judith has been a competent minister, and will quickly be able to pick up the Police and Corrections portfolios that she has successfully held before."
Ms Collins resigned as a minister just weeks before last year's election after allegations she was involved in a campaign to discredit the then-head of the Serious Fraud Office, Adam Feeley.
That followed months of controversy over her support for the dairy export company Oravida, to which she has close personal ties.
Mr Key said he believed Ms Collins had learnt from her past mistakes.
"As I said to Judith, the important issues now are about the future, not about the past and relitigating things.
"And they are actually about all of us acknowledging that we have experiences and, actually, as politicians, we make mistakes. I make plenty of them, I try not to repeat them and I learn from them.
"But no-one's perfect and no-one gets everything 100 percent right. I suspect the 12 months she's had on the backbench has given her a chance to reflect on that a little bit more, and I think it will make her stronger as a minister."
Ms Collins told Checkpoint her first meeting would be a briefing with Department of Corrections chief executive Ray Smith over an ongoing investigation into allegations of organised fighting and other issues at Mt Eden Prison, which is privately run by Serco.
"I want to get to the bottom of it and make sure that we do have a well-functioning prison," she said.
She refused to be drawn on whether the government should exit its Serco contract, saying she was not going to jump to conclusions.
Corrections was a great portfolio but needed a firm pair of hands, Ms Collins said.
"I think the Prime Minister's shown great confidence in me. He's always said that he's had 100 percent confidence in me as a minister to get the job done," she said.
"I'm just very pleased to ... be back."
Mr Key had announced an end-of-year reshuffle, prompted by the departure of Trade and Climate Change Issues Minister Tim Groser from Parliament to take up the role of New Zealand Ambassador to the United States.
He will resign from Cabinet and Parliament on 14 December, enabling him to fulfil his responsibilities at this month's international meeting on climate change in Paris.
Paula Bennett will pick up Climate Change while Todd McClay will take on Trade.
Simon Bridges holds the portfolios of Energy, Transport and Associate Climate Change, but Mr Key said he was advised by the Cabinet Office there might be a conflict if he was given full responsibility for climate change.
"I personally thought in principle having him as Minister of Energy and of Climate Change was at least challenging as a conflict and, as you'll be aware, we've got a review that's going to be undertaken into the ETS [Emissions Trading Scheme].
"It is a portfolio that needs someone with good political nous, and some dexterity and actually I thought Paula would bring that to the job."
Todd McClay hands Revenue to Michael Woodhouse, who has lost Police to Ms Collins.
The Local Government portfolio will now go to Mr Lotu-Iiga.
Mr Key offered ACT leader David Seymour the ministerial portfolios of Minister for Regulatory Reform and Associate Education Minister. That offer was declined, he said.
"As he [David Seymour] wants to see through his member's bill on end of life choice.
"He is also focused on continuing to rebuild the ACT party and working hard as the new MP for Epsom.
"I respect his decision and look forward to continuing to work closely with him in his current roles."
Mr Groser will take up his new post in Washinton early next year, replacing Mike Moore - who Mr Key had said was returning to New Zealand due to health issues.
Maureen Pugh from the West Coast will replace Mr Groser as a list MP.