A witness to the latest Covid-19 border debacle has described how the man absconded from the isolation hotel by casually strolling through a gap in the fence which the wind had blown open.

The government is now looking at tightening security and bringing in police guards after the infected man's 70-minute jaunt around central Auckland.

Promising that isolation failures were a thing of the past, three weeks ago the prime minister brought in the Assistant Chief of Defence, Darryn Webb, for a tougher approach.

Prime Minister Jacinda Ardern said during the announcement: "We need the rigour, we need the confidence, and we need the discipline that the military can provide".

Instead, a 32-year-old man in isolation, who was awaiting a Covid-19 test result that would later come back positive, simply strolled out of the Stamford Plaza Hotel into the middle of Auckland city.

A security guard saw him leave but initially thought he was one of the workers replacing a section of fence around the building.

A fellow guest, Drew, had popped down to stretch his legs in the cordoned off walking area with his partner.

"As we were down there, we just saw this guy walk out and thought that was a bit weird but we thought he was security, who can come and go. Me and my partner were joking about it, like 'imagine if he wasn't security'," said Drew, who did not want his last name used.

They only realised something was up later when the police arrived and they gave statements on what they witnessed.

It is the second escape from isolation; on Saturday a woman at the Pullman Hotel got out by climbing over a fence and absconded for about two hours before being found nearby.

She was charged under Covid-19 laws. The punishment is a maximum six months in prison or a $4000 fine.

The latest breach has forced yet another "rapid review" of security. But Drew said it was already stringent - the Stamford had four security guards on every floor and one at each emergency exit.

"It's fully guarded - I give full credit to the staff here - but it was raining and quite windy, and the fences have these mesh things on, so when the wind hit it pretty much just opened the gate.

"The security guards are in their own little room but they monitor it. I think he just casually walked out. Just the minute or two that no one was there, he was just out the door."

He said only five people are allowed in the smoking and walking areas at one time.

Knowing the man had tested positive made the hotel stay a little less comforting.

"It's a bit unsettling to be honest with you. We don't know where he's been, what floor he's been on, and we're cautious about what we do now. We were before, but this has just made it a little bit worse."

Rules at managed isolation hotels are much more relaxed than for quarantine facilities; people are allowed access to communal areas for exercise or fresh air.

Public Health Professor Michael Baker said new arrivals should be confined to their rooms until their compulsory test on about day three came back negative.

"[New arrivals would be] treated differently, so that the chance of them leaving the facilities, or mixing with local people or things going wrong is minimised," Baker said.

He warned of more breaches as the number of people in managed isolation grew. It only took a look across the Tasman Sea to see how serious the situation could become, Baker said.

"They have now a major outbreak that appears to have been at least partly driven by lapses or breaches in the management of their quarantine and isolation facilities. I think that's a really terrible reminder of the situation we really have to avoid in New Zealand."

The government said it had no plans to keep people confined to their rooms until they returned a negative first test.

"Confining all people to their rooms until they receive their first negative Covid-19 result (likely to be four-five days after arrival) is not currently being considered," a Covid-19 response group spokesperson said in a statement.

The man returned to the hotel voluntarily. He has not yet been charged with anything, but police say it is likely.

As for what he did in the supermarket for 20 minutes, Countdown said he bought toothpaste, browsed the health and beauty aisle, and took some selfies.

Officials have been trawling through CCTV footage to see where else he went.

Via rnz.co.nz