The association for defence lawyers wants an urgent review of all COVID-19 prosecutions in light of a massive case backlog in the district court.

Ministry of Justice figures show police laid 989 criminal charges over restriction breaches during alert levels 2, 3 and 4.

Just over 600 charges, most falling under the Health Act, were laid during the official alert level 4 lockdown, at a rate of 129 charges a week.

This rate jumped to 140 charges a week during alert level 3, before tapering off to just 16 charges a week during alert level 2.

Each of these charges were laid in the district court; the country's largest and busiest jurisdiction that is already dealing with a significant case backlog.

Defence Lawyers Association co-chair Elizabeth Hall says each of these prosecutions should be scrutinised before they take up more time, money and resources.

"Before we overwhelm the criminal justice system even furthe,r there needs to be an individual review of each of the prosecutions.

"There will be inconsistent charging decisions that have been made, many breaches will be minor or inadvertent and that's of course without commenting on the legality of the breach prosecutions as a whole."

The legal standing of the COVID-19 lockdown is the subject of a judicial review that will be heard at the High Court in Wellington next week.

Former parliamentary counsel Andrew Borrowdale has filed the review, arguing the Director-General of Health, Dr Ashley Bloomfield, exceeded the powers given to him under the Health Act.

If successful, it will mean those charged with breaching lockdown restrictions should not have been and could potentially claim damages under the Bill of Rights.

Elizabeth says setting aside the now-contested legality of the lockdown, the Police Prosecution Service could review its COVID-19 cases to help ease the backlog.

"There is a massive backlog in New Zealand's courts and we have a thousand prosecutions here which, if they are urgently reviewed, may mean only some continue."

However, Otago University senior law lecturer Bridgette Toy-Cronin says withdrawing these COVID-19 prosecutions is a bad idea.

"If you ask everyone to follow rules and those rules are in place at the time and some people breach those, I think most people would find it quite hard to swallow that in retrospect that gets dropped because it all worked out okay."

She says withdrawing some of the cases may also undermine future restrictions or another nationwide lockdown.

"So it would have potentially on-flow effects which would be that people would say well last time it got dropped, doesn't really matter, don't need to follow it.

"And then of course there's the signalling effect to those people who are in managed isolation facilities at the moment that these rules are here but we don't really take them seriously."

Elizabeth says even in light of a potential second lockdown, each COVID-19 breach prosecution should be urgently reviewed to determine if it can be dealt with out of the court.

"Certainly with every criminal prosecution though, it's appropriate that the prosecutors review whether the prosecution needs to be brought, whether there is sufficient evidence to bring the prosecution and whether there is some alternate way of dealing with the behaviour, short of dragging someone through the criminal justice system."

RNZ asked the Police Prosecution Service if it will consider urgently reviewing the COVID-19 prosecution cases.

In a written statement, a police spokesperson says charging people over lockdown breaches was a last resort, typically used when a person had already had warnings.

They say as is the case for all cases, COVID-19 prosecutions are dealt with on a case by case basis and police diversion may be available as an alternative resolution for some people.

-RNZ/Anneke Smith.