National wants to grill the Police Commissioner about the Parliament occupation and riot but the Government says any review must be free of political interference.
The occupation ended on March 2, when rioting broke out and protesters and police were injured.
National's justice spokesman Paul Goldsmith said MPs should have the chance to question commissioner Andrew Coster about the 23-day occupation and its aftermath.
"The riots in front of Parliament and the occupation were a huge event and it shouldn't be swept under the carpet," Goldsmith said.
"Labour MPs have refused to allow us to bring the commissioner in and get some basic questions answered. And a transparent Government wouldn't be doing that."
Goldsmith said Speaker of the House Trevor Mallard had already said select committees should be asking about important matters.
"But the Labour MPs block it at every turn," Goldsmith said. "They had no excuse really, it just didn't suit them."
He said people deserved to know why the occupation expanded so quickly on Parliament's grounds, and why it ended in mayhem.
Police Minister Poto Williams today said the Independent Police Conduct Authority was the correct place to investigate the matter.
Williams said it was important for police to have operational independence, and that was incompatible with political interference.
"It's my view that the place it should sit is with the IPCA."
Williams said she could not say if any broader review about policing of the protests was imminent.