A Taranaki iwi is calling for an immediate review of New Zealand Petroleum and Minerals which it says can no longer be trusted.
A State Services Commission report has found the private security firm Thompson & Clark had an inappropriately close relationship with the Ministry of Business, Innovation and Employment unit which manages the country's mineral and petroleum resources.
It also found that the firm, which was hired by some government agencies, treated so-called "issue motivated groups", including Greenpeace, the Green Party and iwi as security threats.
Ngati Ruanui has been actively opposed to a proposal to mine ironsand from the seabed off the South Taranaki coast.
Leader Debbie Ngarewa Packer says the report reflects the iwi's experience that government agencies were biased against it.
"While we are outraged we're also not surprised because this was exactly what we were complaining about and experiencing firsthand that the MBIE Petroleum and Minerals section had an absolute bias.
"They've abused their powers and used delegations way beyond what's expected ethically and I think legally as well."
Ms Ngarewa Packer said serious questions needed to be asked of the MBIE unit.
"What it highlights to us as Ngati Ruanui is that there needs to be a full scale review of the New Zealand Petroleum and Minerals. They can't be trusted.
"And certainly in absorbing the shock, we'll be assessing the possibility for official complaint to the appropriate services."
Ms Ngarewa Packer said it appeared the iwi had got off lightly and had appeared in newsletters and been monitored during protests.
She said it was hard to fathom the level of surveillance placed on other interest groups.
"It's just not acceptable and it's not what we as New Zealanders expect to see. Our officials parading around in corrupt services and engaged in deliberate spying."
Ms Ngarewa Packer wondered what ministerial level influence had been involved in the decision making.
"It's highly unlikely that officials behave like that with out some type of ministerial endorsement and I think there is still a lot more to be shaken out of the tree on this.
"How endorse this? How long has this been going on? What did the minister at the time know? Some of the research we've seen shows this has been going on for three successive governments."
Ms Ngarewa Packer did not think the resignation of Southern Response chair Ross Butler would be the last in the fallout from the report.
"I think they'll be a lot of officials in Wellington that will be ducking for cover. There's been one man whose already fallen on his sword and I expect there will be others."