Random checks of 13 managed isolation & quarantine (MIQ) hotels in February and March found staff shortages, PPE supply problems, returnees left to mingle in a lift lobby and bus drivers not wearing - or refusing to wear - the required N95 masks and eye protection.
The Ministry of Health (MoH) has released more than 100 recommendations it made in the latest round of surveillance audits - noting improvements since December and January.
In one instance observed by auditors, a bus was returning to an MIQ hotel after taking returnees on the 30-minute drive back from an outdoor exercise area.
As it rolled up to the entrance, staff told returnees they would have to sit on board for a while, because someone in the hotel had tested positive for Covid-19 and the lobby was being deep cleaned.
For another 25 minutes they sat and waited as did the driver, who was wearing gloves and a medical face mask.
The bus had been cleaned with a fog gun but the surfaces hadn't been wiped. The driver didn't know he was meant to wear an N95 mask and refused to wear eye protection.
Epidemiologist Nick Wilson said it was "a real concern" that people in the system were refusing to wear the appropriate protective equipment.
"Those people should be moved to jobs where they're not in any contact with infected people," he said.
"Now that we're experiencing these more infectious variants of Covid, it really is completely inappropriate for people not to be using state of the art equipment."
That driver was among a total of nine drivers recorded wearing less PPE than they were meant to, across four hotels, in the latest audits.
Six of them were transporting new arrivals, two were driving buses to exercise areas, and one was transferring a Covid-19 positive patient to quarantine.
The MoH had spoken to bus companies, and bus and van drivers had subsequently undertaken mask fitting and training.
In other findings, one hotel had to change its exercise roster after some 20 people were left in a small lift lobby, unsupervised, for 20 minutes.
PPE supplies have been restocked after two hotels were seen running short due to delivery problems.
Two hotels were short staffed, one with just 50-60 per cent of the base roster healthcare staff it needed.
Wilson said it was great that audits were happening but he was surprised at the extent of the failings.
"These type of problems should have been, at this stage, extremely rare after a year of operating MIQ. It's a fundamental concern that this frequency of problems is still occurring in the system," he said.
He believed two underlying "design flaws" were contributing: People sharing smoking and exercise areas, and people being bussed to exercise.
"These are things that just don't happen in other countries where they're running similar hotel-based MIQ systems," he said.
A briefing to Covid-19 Response Minister Chris Hipkins showed a 48 per cent improvement since the last round of audits.
In December and January the MoH audited all the hotels, finding 19 "high-risk" gaps and making more than 400 recommendations.
Seven hotels needed more staff and three hotels didn't have outdoor furniture in their cleaning programme.
One had to move its exercise area to a place that wouldn't "put the public at risk of exposure to Covid-19" and one was told to stop allowing ball sports in communal areas.
This week Aucklander Grace McCartney finished two weeks MIQ in the Novotel Ellerslie.
She said she felt safe and was impressed at the procedures and kindness of staff, right from the speedy check-in.
"It was good, I think that they must have gone through a lot of processes and changed it a lot to create the efficient way they do it now," she said.
Epidemiologist Michael Baker was relaxed about the findings.
As long as they are acted on quickly, MIQ seemed to be running smoothly, he said.
"We've probably got one of the most sophisticated border systems in the world, but we just have to keep refining it. We have to keep being very open and honest about when things go wrong and describing them in that way, then looking at systematic improvements. That's, I think, how we get ahead of the virus and stay ahead."
Baker wanted health officials to consider a different system for categorising findings - referring to "hazards", "near misses" and "border system failures" rather than putting the onus on individuals, or referring to breaches.
The Ministry of Business, Innovation and Employment said the findings categorised as "high risk" had all been addressed.
It didn't specify the changes, but said they related to the management of laundry, staffing, cleaning, waste and infection prevention and control.