Ginny Andersen will be the Government's new Police Minister after Stuart Nash's resignation last week.
Andersen was only sworn in as a Cabinet minister earlier this year. She is one of the Government's lowest-ranked ministers.
Prime Minister Chris Hipkins said she worked for the Police for 10 years, has an interest in the Police portfolio and is a former Justice Select Committee chair.
He said he has confidence she can do the job and she will hold her own.
"When I've looked at what I want to see from the Minister of Police, I think she's very well-suited to take up that role," Hipkins said.
Asked what it said about the Government's priorities around crime that he has chosen a low-ranked minister to take the job, Hipkins replied it said nothing.
"You will know that the Minister of Justice sits on the front bench. Many of the policy issues that the police deal with are covered by the Justice portfolio and, of course, I have an interest in this as well," he said.
"I can provide an absolute reassurance that law and order and crime will continue to be a key area of focus for the Government."
But Mark Mitchell, National's police spokesperson, said it sends a signal that "Labour has clearly given up on law and order".
"They've appointed a minister with less than two months experience at the bottom of the Cabinet rankings at a time when the country is experiencing the worst crime levels it has ever seen."
Barbara Edmonds will take over Andersen's associate Immigration portfolio.
Nash last week resigned as Police Minister after admitting he once rang the Police Commissioner to suggest he appeal a court judgement. That's a breach of the Cabinet Manual as ministers aren't meant to comment on or involve themselves in prosecutions or sentencing.
A day later, it emerged Nash had also once nearly faced a contempt charge after going on the radio and saying the killer of slain police officer Matthew Hunt should receive a lengthy sentence. The Solicitor-General ended up recommending the Attorney-General give Nash a telling-off.
But it didn't end there, with Prime Minister Hipkins on Friday demoting Nash and placing him on a final warning after it came to light that Nash had used inappropriate processes to advocate on an immigration case.
"However it is also clear in his pattern of behaviour that Stuart is not acting to achieve personal gain from his actions," Hipkins said last week. "The cases in question represent more his desire to get things done in his portfolios and on behalf of his communities."
Nash retains his other ministerial portfolios, including Economic Development and Forestry. Opposition parties have called for him to be sacked from Cabinet entirely.
He was re-appointed as Police Minister earlier this year after holding the portfolio last term. Prior to his reappointment, Poto Williams and Chris Hipkins held the role.