New Zealand police acted unlawfully and unreasonably during armed raids near a small Maori settlement in 2007, an independent report has said.

Police accepted the findings of the Independent Police Conduct Authority report on Wednesday, but said they were targeting military-style camps based in Ruatoki Valley in the remote Urewera mountain range of New Zealand's north island and the operation had to be taken in context.

The Maori tribe of Tuhoe called for a formal police apology after the report said that police unnecessarily intimidated people during the operation and acted unlawfully in establishing road blocks and detaining people during the raids.

The police arrested 18 people in the raids, which uncovered illegal firearms and Molotov cocktails, and sought charges under the Terrorism Act.

Only four people stood trial and were found guilty of firearms charges, but they were not found to be part of an organised criminal group.

Prosecutors had said that the group was planning to use guerrilla warfare to achieve self-determination in the Tuhoe region if negotiations over the issue with the government had failed.

'Unjustified and unreasonable'

The report found that the detention of some Ruatoki residents while their properties were searched was "contrary to law, unjustified and unreasonable".

With regard to road blocks established by police in the towns of Ruatoki and Taneatua, Sir David Carruthers, a judge and chairman of the Independent Police Conduct Authority, said in a written statement on Wednesday: "Police had no legal basis for stopping and searching vehicles or photographing drivers or passengers."

The report also found that police planning and preparation for the establishment of the road blocks was deficient and intimidating.

Peter Marshall, New Zealand's police commissioner, said that he accepted the report's findings and apologised for the impact on "innocent residents of the Ruatoki Valley and elsewhere", but later said he offerred no apology to those who were involved in the investigation.

Ruatoki residents said they were still traumatised by the actions of police during the raids and the Tuhoe was seeking a formal apology in a face-to face meeting.

Ruatoki resident Molly Turnbull said police acted like "terrorists" during the operation. "It's something you read about in the movies, not in our community," she said.

'Significant changes'

Marshall said in a written statement that the police had made significant changes to address many of the issues noted.

But he said the context of the anti-terrorism operation involving more than 300 police was important.

"It followed an almost two-year investigation into a group of people involved in military style training camps using Molotov cocktails, semi automatic rifles, threats to kill people and destroy property," Marshall said.

"When Police executed the 41 search warrants they found 26 firearms. Seventeen were found in Ruatoki including a loaded pistol under the mattress of a suspect."

But he apologised for police officers' failure to meet expected standards when carrying roadblocks in Ruatoki and the town of Taneatua, and five of the 41 property searches.

The report cleared the decision of Howard Broad, the former police commissioner, to authorise the raids and said that he was justified to do so.