A modeller says planned Covid-19 border changes will increase the spread of the virus around the country and it's worrying.
The Government says it's likely the country will move into a new traffic light system soon after 29 November - less than two weeks away.
It will adopt the new vaccine certificate system too, in changes aimed at allowing Aucklanders to travel while providing more time to lift Covid-19 vaccination rates elsewhere.
That's planned to start happening from 15 December.
Canterbury University Professor Michael Plank told Morning Report he's concerned about what will happen next.
"I think when the border opens, we will inevitably see cases cropping up around the country. It's good that there's a requirement for people to be either fully vaccinated or to test negative. But of course, that's not a guarantee.
"Also, one in five cases at the moment is in under twelves and under twelves can't be vaccinated, and they're exempt from the testing requirements. So, I think it is inevitable we'll see cases.
"The biggest concern is if those cases find their way into communities with low vaccination rates, they could spark serious outbreaks."
