Plans to reconnect New Zealand with the rest of the world will be set back, potentially by months, by the current Covid-19 Delta variant outbreak in the country.

University of Otago epidemiologist professor Michael Baker told Morning Report that was partly due to Aotearoa's limited capability to launch new initiatives - but there were multiple reasons reopening would be pushed back.

"The most obvious one is exactly what we've been talking about, that our capacity to launch new initiatives is limited," Baker said.

"It's a finite capacity, and so much of it is now being taken up with this … battle against this outbreak, so that has occupied probably a couple of months of effort by the time it's finished, so that will inevitably push out any complex plans for reconnecting with other countries to a greater extent.

"That will involve, you know a trial of quarantine-free travel, which itself will be reasonably complex, but the other big change of course, is I think all the countries we're going to be connecting more with now have the Delta variant - it's absolutely dominant.

"It's taken over the world, essentially, so that just makes it that much tougher to do this."

The response to the current outbreak had pushed the system to maximum capacity, he said.

Despite that, Auckland and frontline workers were doing an exceptional job and the outlook was positive.

"This outbreak ... will inevitably push out any complex plans for reconnecting with other countries to a greater extent" - Professor Michael Baker

As for essential workers - who have been given another week to provide proof they've undergone a Covid-19 test and can cross Auckland's boundary - Baker said the delay was a "moderate gap in our defences".

"Obviously at the moment Auckland is still under very tight controls and the rest of the country isn't, so you could have a scenario where an essential worker in Auckland - and they after or are at higher risks because they are travelling around the city, they have more contacts - and they could get infected with this virus, they could travel across the border or travel around the country.

"And of course, at level 2 they could go to somewhere to have a meal, they wouldn't have to have their mask on, they could potentially infect other people in that indoor environment, so that's the worst case scenario.

"I don't think it's a high probability, but it is a weakness that we should have been able to stop and then plug that gap."

"I think the only option is to advise this workforce that they must take the alert level 4 with them, which means behaving very differently when they are visiting other corners of New Zealand and that means not going to indoor venues, potentially having meals in their rooms, taking other precautions, wearing masks at all times.

As for the debate about rapid testing for Covid-19, Baker said saliva testing was just another way of getting a specimen for PCR testing.

"It actually doesn't make a huge difference. I mean it is more convenient, particularly for people who've been tested regularly, so it is a great option to have particularly for frontline broader workers, and so on ... in this instance, I don't think it was the critical measure...

"So whether it's a nasopharyngeal swab or a saliva test, it still requires the same logistics of getting people to a testing location."

Source: RNZ Morning Report)