A plan to help fight terrorism in prison highlighted "Māori nationalist groups" as a "threat to public and community safety" through "violent action".
It has earned the Department of Corrections a rebuke from its minister Kelvin Davis, who described it as "unnecessary, provocative language".
The concern about "Māori nationalist groups" emerges in a list of threats identified by Corrections released through the Official Information Act.
It also listed Islamic extremism and jihad, along with far right activists and groups using violence to achieve political aims.
When asked about the statement, Corrections backed away from the comments.
"We have no information to suggest that there are any Māori nationalist groups in the Corrections environment."
The list came from notes of a forum hosted by Corrections in March 2017, taken from the introductory welcome by a prisons' executive.
• This is how our security services expect terrorism to strike New Zealand
• A little less danger? Deadly threats to New Zealand fall
• Terror raids: Rangi Kemara 'screaming into the void'
• Homegrown terrorism threat is angry young people adrift from society
The forum followed on from work done as part of the Government's wider anti-terrorism measures.
Davis said work by Corrections to manage violent extremism helped meet its top priority of public safety but he had never been briefed on, or heard of, "Māori nationalist groups".
"I've received no advice on any threat from extremist Māori groups, and frankly it's disappointing to use unnecessary, provocative language like that while we're building closer partnerships between Māori and the Crown."
Davis - who is also minister of Māori-Crown Relations - said he intended reminding Corrections of this.
The Herald on Sunday also spoke to well-placed sources in Corrections, government and the criminal justice system who were baffled by the reference.
Justice reformer Sir Kim Workman said: "I struggle with that myself. If there are any, I certainly aren't aware of them."
Likewise Denis O'Reilly, lifetime Black Power member and justice reform activist. "It's a fantasy."
He said he had never heard concerns raised of "Māori nationalist groups" despite long involvement in efforts across community, gang and government groups.
O'Reilly said it had resonance with lurid Truth tabloid headlines of the 1970s which depicted Māori in an adverse, militant role.
"It's in the lexicon, buried in the subconscious. It lingers."
A long-time prison guard, speaking anonymously, said he was also unaware of such a threat.
There had been concerns about the potential for growth in Islamic extremism at a prison in one North Island region, he said.
While still on Corrections' radar, he said the situation largely managed itself with organised gangs in prison taking issue with the possibility of losing recruits.
He said there had also been concerns prior to Tūhoe activist Tame Iti's imprisonment over his role in the Urewera training camps which caused a terror-scare a decade ago.
While other inmates did gather about Iti, the guard said the support the veteran activist received was peaceful and there was no hint of trouble.
Police eventually apologised to Tūhoe over the hurt caused by the 2007 raids, which saw illegal road blocks seal off the towns of Ruatoki and in Taneatua during the hunt for those believed to be involved in military-style training camps in the Urewera bush.
The Sunday Star-Times found itself embarrassed a few years earlier after it ran a story purporting to expose a NZ Security Intelligence Service operation targeting Māori.
It emerged it had been hoaxed and no such operation existed.