National's new Corrections Minister Judith Collins is calling on Serco bosses to "front up".
Prime Minister John Key reinstated Ms Collins as Minister for Corrections and Police yesterday in a surprise Cabinet reshuffle.
Ms Collins says the first thing she aims to do is meet with bosses of the private prison operator to find out what is going on.
"Front up, come and meet me, we'll go through things – I'll probably go and meet you before you get a chance to come and meet me," she told the Paul Henry programme this morning.
"I'll have a look at their reports, I'll find out what's going on and I'll be fair, but I want the best outcomes for New Zealanders.
"There's some stuff that's going well, but what happened at Mt Eden [Prison] was totally unacceptable, and it's not going to be happening again as far as I'm concerned."
Ms Collins' Cabinet reinstatement follows her resignation from the Justice portfolio during last year's election.
Emails stolen from blogger Cameron Slater had implicated her in a campaign to undermine former Serious Fraud Office head Adam Feeley.
But Ms Collins has always maintained her innocence, and says giving in would have tainted her legacy.
"I knew I hadn't done what I was accused of doing, I knew it was false," she says.
"I've always thought that I would come through, but I needed the Prime Minister to make that call, and he did, and I'm very grateful to him for it."