A proposed revamp of the jury system could halve trial times, save taxpayers $20 million a year and might require amending the Bill of Rights.

Justice Minister Simon Power's proposals to revamp the court system - which he believes is being slowed by lawyers milking the legal aid system by encouraging repeat appearances - have outraged defence lawyers.

Mr Power wants to see judges alone - as opposed to 12 jurors - deliver verdicts for people facing charges punishable by less than three years' jail - further upsetting lawyers who believe that could breach the Bill of Rights by denying defendants the right to be tried by their peers. At present, those facing sentences of three months or more can choose a jury trial.

Figures provided to the Herald by Mr Power yesterday show that having judges alone decide such cases, in combination with proposed changes to how charges are laid, would save about 1100 jury trials a year.

With an average jury trial taking at least 12 months, and judge-alone trials taking just six months, trial times would be halved, reducing the trauma for victims and backlogs in overloaded courts.

Mr Power said his figures did not include the costs to defendants, witnesses, victims, lawyers, the Department of Corrections or other agencies. But with those excluded, an average jury trial cost $20,000 and judge-only trials just $2000.

* The Ministry estimates it can cut:

10 per cent of adjournments in non-jury cases.

15-20 per cent of pre-committal adjournments.

10 per cent of post-committal adjournments.

In total, this is about 14,900 unnecessary events a year in the court system.

Source: Simon Power