Manukau District Court Judge Jane Lovell-Smith said renovations at Manukau District Court meant some court rooms would be shut down at different times and something had to be done to relieve waiting times.
She said Manukau dealt with "huge volumes" of cases and something had to be done.
A spokesman from the Justice Ministry could not say what the current waiting time was.
Judge Lovell-Smith said that under the new system, sentencings would be allocated a time slot so victims and defendants would have less disruption to their day.
"For victims of crime, previously, if they wanted to come along, they had to turn up to court like everyone else and wait with no certainty that their case was going to be heard."
The working group would continue to meet over the next six months and a system would then be reviewed by the ministry.
Criminal Bar Association representative John Anderson said his group opposed the "night court'' because it would lead to lawyers and judges working unsociable hours.
He said the idea has been borne out of money saving.
"It is like saying 'let's have surgeons working around the clock'."
Auckland District Law Society court house committee convenor Iain Hutcheson said his organisation raised a number of concerns, including one from female lawyers about walking to their cars late at night.
That was dealt with by an undertaking from Ministry of Justice security staff to accompany lawyers to their cars.
He said he would like to see a review of the model if it was to be rolled out around the country.
Currently, the court building at Manukau is flanked on one side by a temporary construction fence where a $40.6 million court expansion has begun.
Work on the site has ground to a halt after Mainzeal Property and Construction announced its receivership on Waitangi Day.
A spokesman from the Ministry of Justice said Mainzeal's problems would likely extend the time for completion - originally put at November next year but would not affect the double sentencing sessions.
The redevelopment will include a new four-story extension as well as a complete refurbishment of the existing court building. It will also include four new jury trial courtrooms.
