The Police Association says officers were needlessly put at risk when they were sent to evict the Parliament protesters last year without enough protective equipment.
Eighty-two officers were treated for injuries and six went to the emergency room with serious injuries from the riot on the final day of the Parliament occupation.
Officers told the police watchdog, the Independent Police Conduct Authority, that the lack of gear was foreseeable and avoidable.
The IPCA review into the occupation of Parliament last year highlighted the urgent need for more body armour. It was one of several criticisms made about the way senior police handled the illegal three-week occupation in its report released on Thursday.
Association president Chris Cahill told Morning Report it was unacceptable officers were sent out on the day the protest was brought to its violent end with insufficient protective equipment.
"Clearly, officers were put at risk; it was inappropriate."
There were two reasons senior officers took this approach. The first was they did not want to antagonise the protesters by having officers kitted out in full body armour.
However, if police wanted that approach they should have had reserve staff ready "to take over when the violence erupts".
The second reason was police "had dropped the ball over time" in providing suitable training and equipment for public order policing.
"Two big failings that put officers at risk unacceptably."
Cahill said he was "suspicious" that police first tried to break up the protest a day after Police Commissioner Andrew Coster's meeting with politicians on 9 February.
However, ultimately he would accept Coster's assurance he made the decision and there was no political pressure to bring it to an end.
"But what I think has been clearly identified is the need for better understanding of who has control over Parliament; who's the decision maker of what happens; what time it gets handed over to police..."
Cahill said there needed to be a clear structure in place to handle similar events in future.
There should have been attempts by politicians to engage with some protest representatives early on and it might have avoided the violent ending.
"You need to at least give people a chance ... You should try everything first and I don't believe it was done because politics overruled common sense at times."
The lack of planning by senior officers to deal with the protest in the initial stages was criticised in the report and the Police Association agreed it was "one of the biggest failings".
Senior officers seemed to be receiving reports from several parts of the country but by the time they were closely monitoring what was unfolding it was out of control.
The association would look at the eight cases where there might have been excessive force used but given the level of violence officers were faced with the report made clear officers in the main had acted professionally.
Police Commissioner accepts equipment in short supply
Andrew Coster accepted frontline officers did not have enough equipment, more had been ordered and police would continue to assess if they had enough in store to handle future events, he said.
He told Morning Report the IPCA had not suggested anything police had failed to do in terms of planning would have changed the course of the protest.
"What caught everyone out in the situation was the scale of what occurred and the depth of feeling those people brought with them."
He said there was no legal authority on the first day for police to remove protesters or stop equipment, such as tents, being brought into the site. On 10 February the Speaker closed the grounds of Parliament and declared everyone a trespasser, giving police the authority to remove them.
"In our view the threshold for unlawfulness balancing trespass against the right to protest wasn't reached until effectively the Speaker issued the notice the grounds were closed..."
He was adamant that while he had met with Ministers and the Speaker the day before the first attempt to remove the protesters was made he had not been pressured or instructed.
Coster had conversations with former prime minister Jacinda Ardern and Ministers as well as Opposition party leaders about the possibility of them meeting with some of the protesters.
Questioned if he asked any of the political leaders to meet with the protesters Coster stressed it was not his place to ask the politicians to do this but certainly the topic had been raised.
However, the Speaker later issued a notice making it clear politicians would not engage with any protesters until they left Parliament's grounds.
Coster said it would be "unhelpful" to speculate on whether politicians should have found a way to meet with some of the protesters.
Former National Party MP and police officer Matt King who was part of a last year's occupation of Parliament disagrees with some of the IPCA's findings.
It found officers served the public well in the face of "extreme provocation".
King, who now leads the Democracy NZ party, said it got some details wrong, however, it had come up with some good recommendations.
He said the violent end to the protest could have been avoided if politicians had listened to and spoken with the protesters.
"If they could have arranged at least some sort of process so that they could have been listened to I believe this whole violent end could have been avoided."
There were "several people" among the protesters who could have been negotiated with and he was one of them, he said.