Prime Minister Jacinda Ardern has defended Labour's use of majority to block a briefing from police on the Parliament protest because she wants an "independent voice".
Labour MPs last week used their majority on Parliament's Justice Select Committee to block a request for a briefing from Police Commissioner Andrew Coster, sparking backlash from the National Party.
But Ardern said on Monday it was more appropriate for the Independent Police Conduct Authority (IPCA) to investigate the response to the 23-day protest against COVID-19 vaccine mandates that ended in a violent standoff with police earlier this month.
"We're waiting for formal confirmation for what the IPCA, who is independent, intends to do and I expect that we'll hear from them this week," Ardern said at her post-Cabinet press conference.
"I think it would be important for us to look at the terms of reference before making a judgement as to whether or not everything that needed to be included, or that we would expect to be, is.
"If there are areas where we know that there's a public interest that we have a greater understanding to look into, then we'll look at that. But at this stage, we don't have their terms of reference to make that call.
"The IPCA is independent and I think it's important that we have an independent voice in this, particularly because of course, some of the complaints will be coming from those who were part of it, and so I think having the independence is an important part of it."
Ardern threw her support behind Labour's use of majority to block an appearance from police at the Justice Select Committee.
"Ultimately, if you want to have an independent look at what happened, you would seek someone who is able to provide that independent voice, and that would be the IPCA," she said, when asked if Labour's actions were appropriate.
"[The ICPA] have the knowledge, the experience, the operational understanding and the inquiry powers to do that, so they are well placed," Ardern added.
"I would also add that the Police Commissioner does appear before those select committees but not necessarily in an ad-hoc way."
National's justice spokesperson Paul Goldsmith says while an IPCA investigation is appropriate, it won't cover all the aspects that need to be reviewed.
"What about the role of the Speaker? What about the actions from Government Ministers? What can the Police Commissioner tell us about what did and didn't happen?"
Earlier this month former top police negotiator Lance Burdett pointed blame at House Speaker Trevor Mallard for aggravating the Parliament protesters in the early days of the demonstration.
The weekend of February 12 marked the beginning of when the protest took a turn. After 120 arrests and several days of occupation, the weekend came around, and Mallard turned the sprinklers on the demonstrators and blasted music all weekend to try and drive them off the grounds.
The protesters responded by digging trenches in Parliament's lawn to redirect the sprinklers. They also blasted their own music in a show of defiance. The protest then grew significantly, with about 800 vehicles at its peak and more arrests.
Burdett told AM setting the sprinklers on the protesters was "an error" because at that point they just wanted to be heard.
Goldsmith says the public has a right to know what went wrong.
"New Zealanders saw an unprecedented occupation and trashing of Parliament's grounds and its surrounding streets, followed by a fiery and riotous conclusion. How did it come to this, is the fundamental question.
"The existence of an IPCA investigation provides no justification for blocking every other form of inquiry. This is basic democratic accountability."
Ardern said once the Government has received the terms of reference for the IPCA investigation, "then we'll be in a better position to judge whether or not there are gaps".
It's not the first time Labour has been criticised for using its majority to block inquiries. Green MP Chlöe Swarbrick has repeatedly had requests rejected for a briefing from officials on why house price predictions have been wrong.
