All jury trials are off for at least two days for the nationwide Covid-19 lockdown.
And there's plenty of space in jails in case any inmates need to be isolated, the Corrections Association says.
Chief Justice Dame Helen Winkelmann said courts were an essential service in all alert levels but non-priority proceedings were adjourned today and tomorrow.
That included jury trials.
Recent high-profile jury trials included that of an influencer accused of blackmail and sex offences, the Isaac Allen Harnwell murder trial, and the fraud trial of two former Canterbury Earthquake Recovery Authority employees.
Today and tomorrow, courts will only hear "priority proceedings", except for an Environment Court case known as Chen v NZ Transport which will still be heard.
The Chief Justice said priority cases included matters relating to individual liberty, personal safety and wellbeing, or where resolution was time-critical.
For the Court of Appeal, adjourned proceedings are likely to be heard on Friday or Monday, the Chief Justice said.
From Friday, the Court of Appeal, High Court and District Courts will be back to business, but in accordance with relevant alert level protocols.
But Friday's hearings at the Supreme Court, Māori Land Court, Environment Court, Employment Court, and Waitangi Tribunal will be adjourned, except for priority proceedings.
Justice Winkelmann said where possible, court hearings would use remote participation.
Courts have made increasing use of streaming and teleconferencing technology since the Covid-19 pandemic started.
An Official Information Act response showed the Ministry of Justice invested about $8.73 million on Covid-19 mitigation in the first 12 months of the pandemic.
Just over half of that money was for information and communication technology.
"Where an in-person court hearing must take place, attendance in court will be strictly limited," the Chief Justice said in a statement sent overnight.
Face masks in court will be mandatory unless a judge says otherwise.
Most jury trials will be adjourned for as long as alert level 4 lockdown, except where jurors have already retired to consider verdicts.
If juries had already started deliberating, it is expected those trials will resume on Friday.
The Chief Justice said court staff would be in touch with jurors and lawyers to update them about arrangements.
The Pacific Lawyers Association (PLA) said Manukau District Court was only handling custody, but one Youth Court would be available if needed for priority proceedings.
The PLA said people in custody would appear by audiovisual link throughout level 4 at Manukau, Papakura and Pukekohe courts.
Corrections Association president Alan Whitley said the prison muster was now smaller than before the first national lockdown last year, and there was plenty of capacity.
"There's probably about 2000 spare beds."
The most recent muster numbers he'd seen last week indicated a prison population of about 8200.
"There's capacity for Africa," Whitley said today.
This should make isolating any inmates with Covid-19 tenable, he said.
Whitley said the Auckland region had moved in and out of previous lockdowns before with competence and he was confident professionals in Corrections would manage the latest lockdown again.