Prime Minister Jacinda Ardern yesterday announced that New Zealand would shift to the vaccine certificate regime at 11.59pm on Thursday 2 December.

The government will reveal more information for businesses, including sector-specific advice, throughout the week.

Auckland Business Chamber chief executive Michael Barnett said it was great to have a firm date, but many businesses still had questions about the next phase.

"I don't think [businesses] do understand it yet," he said.

Barnett said the government needed to provide clear information to business owners on the rules and how to enforce them.

"What we need is just good communication - the how to - this is what you will need to do [and] this is how you do it."

Read more:

• Explained: What the traffic light system is and how it works
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Māori Party co-leader Debbie Ngarewa-Packer said the government had done a poor job of communicating the changes to the public.

"It's really, really difficult to get your head around."

She said people in Covid-free areas wanted an assurance the rules would be enforced to prevent spread.

"Who is on the ground monitoring and ensuring compliance? Who's doing it all? It actually raises a whole lot of questions.

"We're not clear how it's all going to run and who's going to be making sure it all works."

National Party Covid-19 Response spokesperson Chris Bishop told RNZ the government's communication - "a real sense of... just making things up as we go" - had left the public confused.

He said the muddled process meant the government would now have to push through legislation under urgency.

"It has been literally created and designed in a massive rush and because of that the risk of mistakes is high. Of course, we will all bear the consequences of that."

Bishop said he wanted answers over what exactly would trigger a shift between risk settings for various regions; from red to orange to green. The government has signalled it will reveal those details on Monday.

ACT's leader David Seymour said the date and details could have been announced weeks ago.

"We've had more announcements of announcements than actual useful announcements so far."

Seymour said the government had clearly been unprepared to roll out the vaccine passports needed for the traffic light system to operate.

Read more details on the traffic light system on the government's Covid-19 website.