Parliament review will reveal drinking, cheating, sexual abuse, bullying - Duncan Garner

The AM Show host Duncan Garner says the independent external review into bullying and harassment of staff in Parliament will reveal bullying, harassment, intimidation and unwanted sex.

Announced by Speaker of the House Trevor Mallard on Tuesday morning, the review will establish whether bullying or harassment has occurred, then investigate the extent of the behaviour. The review will include current and former members of staff.

Mr Mallard says "bullying and harassment are unacceptable" and he will take action to make sure staff feel safe and supported.

As of Tuesday night, Mr Mallard's office had taken 100 calls, and on Wednesday morning Garner - a former 3 News political editor - said it should be a "belter" of an inquiry.

"Parliament could be a bomb site by the end of this inquiry. You see that place rewards the winner and the loser is humiliated. The more public the humiliation then job done," he says.

"I expect this review to highlight the total power imbalance between the worker and the MP, the drinking, the relationships, the Wellington wife, the sex, wanted and unwanted, the daily humiliation of the weak and of the wrong."

But The AM Host says Mr Mallard isn't one to talk about improving the parliamentary workplace.

"For Mallard it's a case of the bully going after the bullies really," Garner says.

"I mean who else can claim to have punched out an MP behind the chamber, poor old Tau Henare, then go to court, plead guilty, and live to not only tell the tale but go on to be the Speaker looking into himself and many many others."

Garner knows how bad it can be. Last month he discussed his time as a political reporter and how it changed him.

"I'd worked in Parliament for 17 years, and I'd become like them: mean, combative, cynical and I drank too much. I had to get out," he told Newshub.

Speaking on The AM Show today, he called Parliament a "god damn awful lonely place to work" and reflected on the behaviour he'd seen - and been part of.

"I have seen all this up close and I have been part of it. It's a great place to work until it's not," he says.

"Remember in 1996 Tuku Morgan spent 89 bucks on a pair of undies. Trevor Mallard went after him, so did the media. This was all part of the behaviour there, he was an easy target, a new MP, Maori MP. Not hard to get people outraged at that.

"Looking back, it was racist and shameful some of our approach. I'm sorry Tuku that we did that, looking back. I'm taking ownership of that.

"It was the worst of the worst.  It's a place where good people go to die and the survivors must become feral to win."