The 18 people arrested during the Urewera police raids have sought leave to appeal to the Supreme Court in an effort to have their case heard by a judge and jury.

In December, the High Court ruled that the case should be heard by a judge alone.

Despite opposition from lawyers for the 18 accused, who appealed to the Court of Appeal, the decision was upheld last month.

Suppression orders prevent publication of the reasons for both courts' decisions.

The 18 accused, including Tuhoe activist Tame Iti, face charges under the Arms Act as a result of the 2007 raids.

The trial is due to take place before a judge in the High Court at Auckland next month.

But now the group are taking their fight for a jury trial to the Supreme Court.

Crown prosecutor Ross Burns confirmed leave had been sought.

He said the right to trial by a jury was "very important" but the Crimes Act did allow trial by judge alone when cases were complex and expected to take a long time.

The Urewera case is set down for 12 weeks.

"It is a long time, a long trial," he said.

Veteran activist John Minto said a jury provided public input into the trial.

"Otherwise it is a little in-house decision - no disrespect to judges but they are part of the judicial system," Mr Minto said.

Police credibility was at stake and families had been subjected to distress.

"It's their basic bloody right."

Human rights lawyer Michael Bott, who represented one of the Urewera accused before withdrawing to focus on standing for the Labour Party, said juries provided a "safe ground" between the state and the accused.

He said removing a jury from the trial was tantamount to minimising community involvement in the justice system.

"The judiciary has recognised the importance of a right to trial by jury."

Mr Bott referred the Herald to a finding by Justice Sian Elias and John McGrath in the Supreme Court last year.

In Vincent Ross Siemer v the Solicitor General, the two judges said juries provided a "safeguard against the arbitrary or oppressive enforcement of the law by the Government".

They said the jury was "seen as standing between the accused and the state in a way that judges, who are sworn to apply the law, were not always able to do.

In this way they reflected the attitude of the community in their determination of guilt or innocence".

A separate appeal has been taken to the Supreme Court on admissible evidence.

Iti's lawyer, Annette Sykes, and Rodney Harrison, QC, will take the appeal to the Supreme Court next month.

The nature of the evidence is suppressed.

Police have alleged the 18 accused participated in weapons-training camps at various spots around the country.

In October 2007, more than 300 police made early morning raids on several properties, including the suspected camps.