The police union denies officers were heavy-handed in their handling of a protest in Auckland.
Those protesting against the Trans-Pacific Partnership trade agreement became agitated when they were refused the opportunity to hand over a petition to delegates meeting at SkyCity on Saturday.
Police Association president Greg O'Connor says protest leaders need to be taken to task.
"If they were at all responsible, would have stopped the violence and certainly would not now be condoning it. Their actions really need to be looked at."
Greg O'Connor says there were initially just five officers at SkyCity who had to call for back up.