The Prime Minister issued an epidemic notice under section 5 of the Epidemic Preparedness Act 2006 on March 24, allowing the use of special powers by medical officers in accordance with section 70 of the Health Act 1956.

The Government then triggered a state of national emergency under the Civil Defence and Emergency Management Act (CDEMA) on March 25, giving authorities more powers to manage the virus outbreak.

The three laws allowed the Government to order the closure of premises, with the exception of essential businesses, as well as prohibit mass gatherings, require arrivals into New Zealand to be isolated or quarantined, and order people to stay home.

"In terms of the position on legal professional privilege, there is nothing unusual or different happening here," Parker said. "The Crown, like anyone else, is entitled to claim legal professional privilege in respect of the advice that it receives."

Opposition leader Simon Bridges argued that it's in the public's interest to have the advice released so that it can be scrutinised and MPs can be certain the law was followed.

Parker responded: "I'm confident that the Crown is right in the legal position that we take. We're not releasing the advice but if you want to contest that position that's not for this committee or for me."

He said he takes advice from the Solicitor-General as to whether privilege should be waved but "there is no advice I've had that we should waive it".

Bridges said if Parker is confident the law has been followed then he should release the advice. He questioned the legality of some of the lockdown rules, such as a ban on surfing.

"I remember as a minister releasing legally privileged advice because it didn't make any difference and it didn't worry me."

Parker said the law is "abundantly clear" that governments "can for reasons of public health restrict people's liberties".

Seymour asked Parker if he would release the advice to the committee in confidence, but the Attorney-General said: "I doubt it."