The 18 people arrested during the Urewera "terror" raids have been denied a trial by jury.
Instead, their cases will be heard by a lone judge.
In December the High Court ruled the case should be heard only by a judge.
Despite objections by the defence for the 18 accused, the Court of Appeal yesterday announced it would uphold the High Court ruling.
Suppression orders prevent the publication of the reasons behind both courts' decisions.
The 18 accused, including Tuhoe activist Tame Iti, face various charges under the Arms Act as a result of the 2007 raids.
The trials are due to take place in Auckland in May and are expected to run for 12 weeks.
Prosecutor Ross Burns said last night the decision was "appropriate".
"I can't really comment, but the decision is the decision," he said.
"We applied for a judge-alone trial in order to make the whole thing work as smoothly as possible. The Court of Appeal has agreed that that is appropriate."
Political activist John Minto said the decision was dangerous.
"I think it's really disappointing. It would be better for it to be left up to citizens to decide," he said.
"A group of citizens independent of the state should make the call on these charges. I think it is [dangerous] in terms of public confidence.
"There are big question marks over this case."
Mr Minto said it was "widely regarded" that police overreacted in the raids and charges.
"The police have put their credibility on the line in this case. It will be much better dealt with by ordinary citizens who will look at the evidence and make a reasoned judgment. There is a tendency for different parts of the state to protect others."
Police alleged the 18 accused participated in weapons-training camps at various spots around the country.
In October 2007 more than 300 police officers carried out early-morning raids on several properties, including the suspected camps.