Key Points:

Prime Minister John Key has raised concerns around police using paid informants to infiltrate protest groups, but his Government will not intervene.

Police Minister Judith Collins yesterday said she had been given an assurance by Police Commissioner Howard Broad that police were "meeting their responsibilities" after it was reported that Christchurch man Rob Gilchrist had been paid to supply information from various groups to police over several years.

Police will not confirm or deny Mr Gilchrist's activities, but say they are not targeting peaceful protesters. Mr Gilchrist told the Herald he would like to comment but could not "for all sorts of reasons".

His former partner, activist Rochelle Rees, who claims to have uncovered emails Mr Gilchrist was sending to police detectives, said the Government could not ignore what was going on.

"I completely understand that the Government can't interfere in operational police matters," Ms Rees told the Herald.

"But the issue is that it is the Government that initially set up this [police] unit and gave the funding for that unit, and in the same sense the Government has the ability to take away that funding and that police unit. Or put through legislation to prevent this sort of thing happening."

Police have reportedly been paying informants to spy on groups such as Greenpeace, animal rights and climate change campaigners and Iraq war protesters.

The Government said police needed to remain independent and it has ruled out holding an inquiry.

But Mr Key told TVNZ's Breakfast programme: "We would need to be satisfied, as any New Zealander would, that those being investigated were worthy of investigation, [that] 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 he would be concerned if frivolous investigations led to public loss of confidence in the police's judgment. Police based their actions on a wide range of information, and even environmental groups could "undertake quite violent behaviour".

Police national crime manager Detective Superintendent Win van der Velde told the Herald police had no interest in lawful protesters, but focused on individuals where criminal behaviour was suspected.

Last night Ms Rees issued details of questionnaires emailed to Mr Gilchrist by the police.

They included questions on climate change groups, animal rights activists, and planned anti-American demonstrations.

Green MP Keith Locke said his party's own emails may have been forwarded to police by Mr Gilchrist, and they would be asking the police whether they encouraged this practice.

Animal rights activists have in the past been linked to death threats, cars doused in paint stripper and break-ins in New Zealand.

But Ms Rees said none of the groups she was involved with were connected to any such action.