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Police Commissioner Howard Broad has said he does not believe an inquiry is needed into allegations police have been spying on peaceful protest groups.

Mr Broad today met Police Minister Judith Collins who is deciding whether to launch an inquiry after a report in the Sunday Star Times claimed protesters' personal information was being passed to police.

The Special Investigation Group, set up in 2004 to focus on terrorism threats to national security, has been reportedly paying informants to spy on groups such as Greenpeace, animal rights and climate change campaigners and Iraq war protesters.

Rob Gilchrist, from Christchurch, a key member of various protest and community groups such as Greenpeace in the past decade, was paid to pass on information to the SIG on planned protests, and group members' personal information and sexual relationships, the Sunday Star-Times reported.

He had sent information to an anonymous email address traced to two Christchurch SIG officers, Detective Peter Gilroy and Detective Senior Sergeant John Sjoberg.

After his meeting with Ms Collins this morning, Mr Broad said he did not believe an inquiry was needed but he was seeking more information about the cases.

He defended the use of informants, saying they were used for a range of inquiries including murder.

The SIG was meant to assess threats from individuals who may or may not be members of groups.

"[People who] want to do some damage, they want to do some violent things," he said on Radio New Zealand.

"Our job is to identify those people and do something about it."

Mr Broad said police were not targeting peaceful protesters but if they were alerted to the possibility of violent action or vandalism they acted.

"The threshold is someone or something has alerted us to the fact that there is some real risk that a person might carry their intention through into some violent act."

He expected complaints would be made about the spying and would be seeking additional information himself.

"I will form a judgment. Whether I speak publicly or not is another matter."

Ms Collins said Mr Broad assured her police were working within their responsibilities in their operation of SIGs.

"In a free society such as we have in New Zealand, it is important that the rights of groups to undertake legitimate and lawful activity is upheld," she said.

Ms Collins would not comment further saying it was important that the police were able to operate free of political influence.

John Key

Prime Minister John Key earlier said police should only be investigating groups that present "a real or credible risk to the safety and security of communities".

Mr Key said police investigations were an operational matter and the Government could not direct who it investigated.

But the spying allegations raised some concerns, he said.

"I think the main point here is we would need to be satisfied as any New Zealander would that those being investigated were worthy of investigation, in other words, they present a real or credible risk to the safety and security of communities, not just a group the police target because they feel like it," he said on TVNZ's Breakfast programme.

He said he would be concerned if frivolous investigations led to a loss of public loss of confidence in the police's judgment.

"I wouldn't like an individual group like Greenpeace to be targeted," he said on NewstalkZB.

However, he would be more comfortable if it was individuals who were being investigated rather than organisations.

But he said police based their actions on a wide range of information and even environmental groups could "undertake quite violent behaviour".

Labour leader Phil Goff said the previous government was not aware of the spying activity and he would be concerned if police were misusing the extra funding they had been granted by him, in 2004 as foreign affairs minister, to tackle terrorism.

Mr Goff said that funding was designed to tackle external threats to New Zealand.

"Peaceful protest is not a security threat to New Zealand," he said on National Radio.

"Clearly most New Zealanders would believe that intelligence work is important and necessary, but most of us would be prioritising gang activity, drug trafficking - criminal activity that was a threat to New Zealanders."

Spying discovery

Mr Gilchrist's work with the police was discovered by his girlfriend, animal rights and Labour Party activist Rochelle Rees, who was helping him fix his computer.

Miss Rees said they met at an animal rights meeting. She thought their relationship had been based on common values and goals, and was devastated to learn that he had been spying on her.

"I am disgusted at the police, both for their extreme level of intrusion into my life, and for the way they have used Rob and had him live a lie for 10 years."

This year, Mr Gilchrist said Thompson Clark Investigations, an investigations company employed by Solid Energy, offered him money for information about the anti-mining group Save Happy Valley Coalition.

Coalition spokesman Alan Liefting said although it was frustrating that private investigation firms paid members to infiltrate protest groups, it was "totally disgusting" for the police to be doing the same.

"This is not Russia, and New Zealand shouldn't be turned into a Big Brother police state," Mr Liefting said.

He believed Mr Gilchrist, who has been involved with the coalition, was paid about $600 a week by the police.

"My beef is really with the police for dangling money, public money, in front of protest group members, such as Gilchrist, in an attempt to [turn] them into spies," Mr Liefting said.

"Is this not a waste of police resources?"

Green Party police spokesman Keith Locke attacked the police surveillance as Stasi tactics and covert political operations that undermined democracy.