National leader Simon Bridges said the Government hadn't done its homework on how many businesses will go out of business and the impact on the health system for an additional five days in lockdown.
Bridges said the decision on schools opening had been poorly explained.
"I think ultimately there has been a communication problem."
Bridges said it would be helpful to see the advice in writing that the Government had relied on "in black and white" to understand the rationale.
On Winston Peters returning to work, Bridges said he thinks Parliament needs to come back.
"Zoom ain't going to cut it."
He hadn't considered what Peters should do and said "ultimately a matter for him".
Bridges said they'd wait for the Business Committee to make a decision on how many MPs would come back.
It could see alternating MPs sit in Parliament depending on what questions needed to be asked.
The critical comments on his Facebook post criticising the five-day extension, Bridges said people were entitled to their view.
He said there were also "very strong views on the other side of this" from other New Zealanders who were struggling under the lockdown.
He didn't expect 55 MPs back in Parliament and was waiting for the rules from the Business Committee before deciding what their approach would be.
The focus of the Epidemic Response Committee would be health with various industry groups appearing before it.
PPE, testing and tracing were all issues and needed to gear up and Bridges said he didn't have sight over whether ministers could have done more to make that happen more quickly.
• Covid19.govt.nz: The Government's official Covid-19 advisory website
The Committee was set up as a substitute for Parliament and it would be worth continuing it as long as restrictions were in place, Bridges said.
It was possible the Prime Minister could be asked to appear at the committee, he said.
But that wouldn't happen this week.
Bridges said there could have been a better balance between the health benefits of staying in lockdown versus what impact it had on small businesses.
This summer will be critical to discover if the sharks have started returning.