Attorney-General David Parker has accused the Opposition of a "dangerous" attack on public servants and the separation of powers between Parliament and the courts.
The Epidemic Response Committee (ERC), chaired by National Party's Simon Bridges, has summonsed the Solicitor-General, the Director-General of Health, and the Police Commissioner to help ascertain the lockdown's legal status.
Bridges also wants the Crown Law advice released so the public can see whether lockdown under level 4 and 3 was legal.
"I supported going into lockdown but the government had a duty to New Zealanders to ensure that it was enforced legally," Bridges said.
"David Parker needs to urgently release the advice to clear this up," he said.
"We also need to be sure that the Attorney-General and Police Commissioner have not misled Parliament when they appeared at the Epidemic Response Committee.
"Release the legal advice... New Zealand must be ruled by law, not press conferences."
In a Facebook livestream this afternoon, Parker said the Crown Law advice was privileged but concluded there was "no gap in the powers of enforcement under levels 3 and 4".
It was also the subject of a judicial review that would be "resolved soon" and the courts were "where, quite rightly, disputes are determined".
The Opposition was going down a "dangerous route by targeting public servants" when they no doubt would have been willing to appear with a "simple request", Parker said.
"Doing this in order to attempt to force the disclosure of privileged legal advice... the committee is attacking in my view not just fair processes but also the privileges of the Court."
He said the "current attack is an attack on community; the separation of powers between Parliament and the Courts".
Parker also questioned whether the ERC was over-reaching its own powers and would ask the Speaker of the House to refer the matter to Parliament's Privileges Committee.
Parker said Bridges was offered a confidential briefing on the legal advice.
Bridges said that was a clear attempt to gag him and so he declined.