"You simply can't do it - think about the practicality of it. We already know that Aucklanders are either around 90 per cent at least first vaccination and you're going to have most of these people have their second vaccination when Christmas comes," Collins said.
Collins said she would not back a hard border, but would not be drawn on whether a soft border would be preferable.
"You can't have people stopped at the border," Collins said.
"We're not going to end up in a situation where there can be mass checking of everyone at the border."
Collins briefly suggested the Government could use a spot check system, but then refused to elaborate on that idea - saying it was all "hypothetical" until the Government had vaccination certificates ready.
"Could be a spot check - but that is up for the Government to come up with," Collins said.
"They also need to have… all of this is predicated on them having a vaccine certificate," she said.
National leader Judith Collins and Covid-19 Response spokesman Chris Bishop are not on the same page when it comes to borders over summer. Photo / Mark Mitchell
She would not be drawn on whether a soft border using random spot checks would work.
"You can't check if you don't have a certificate for the vaccine."
"It's simply not going to be practical until they have a vaccine certificate available or they have rapid antigen testing - I'm not going to have a hypothetical answer a hypothetical because the Government hasn't either of those," Collins said.
Covid-19 spokesman Chris Bishop has a clearer answer - simply, once vaccination rates were high enough, there would be no need for any checks.
"Our preference is once Auckland is released from the Auckland prison - just let Aucklanders leave and I don't think there should be a need for saliva checks or vaccination status or anything like that," Bishop said.
Instead, Bishop believed personal testing in the community would do the job of making sure infection rates stayed under control.
"What we should have as I've been saying for many months now is ubiquitous rapid antigen testing in the community so that people who do show symptoms of Covid and people who want to self-diagnose themselves can go to the supermarket or the pharmacy like they can in many other countries around the world including Australia and get a rapid antigen test," Bishop said.
High profile National MP Chris Luxon - who polled just one point behind Collins as preferred prime minister in Monday's 1 News-Colmar Brunton Poll - was also asked for his view on the Auckland boundary.
Luxon said he did not support a hard boundary around Auckland over summer.
He began detailing why he held this view, but quickly thought better of it.
"Because I think… that… I'm not going to comment on that, I'll leave it for Chris Bishop to comment later," Luxon said.
"I'll leave that for Chris Bishop to comment as the Covid spokesperson," he said.
