A Rydges Hotel maintenance worker who contracted Covid-19 used a lift shortly after an infected guest in the managed isolation facility, investigations have revealed.

The worker tested later positive to Covid-19 on August 13, but his strain of the virus was different to that involved in the big Auckland cluster, which has forced the city into a two-week level 3 lockdown.

Instead, it matched the strain of the female guest, who had earlier flown in from the United States before testing positive for Covid-19 and then being transferred a quarantine facility.

Today, director general of health Dr Ashley Bloomfield said the worker had now been found to have used a lift "very shortly" after the Covid-positive woman from US used it.

Bloomfield described it as a "strong line" of investigation.

He said if the worker had been infected in the lift, it would most likely have been from a contaminated surface rather than droplets circulating in the air of the lift.

The worker had been in the lift only a "matter of minutes" after the woman, data from swipe cards showed, Bloomfield said.

He also confirmed that two nurses who visited the Covid-positive woman in Rydges have not contracted the virus.

Earlier, health authorities had confirmed the maintenance worker definitely contracted the virus from the woman, who had returned from the US, based on them having the same strain of Covid-19.

However, there had earlier been no known direct physical links between the two.

Tricky virus

Earlier it was revealed the worker went to work with a cough for two days, but put it down to a pre-existing health condition.

He passed a temperature check at work but tested positive when mandatory testing of staff was introduced late last week.

Prime Minister Jacinda Ardern said that showed how tricky Covid-19 was given it shared symptoms with many other health conditions.

Bloomfield revealed the man was tested on August 13 as part of the mandatory testing regime for all workers at managed isolation and quarantine (MIQ) facilities.

He had his cough on August 11, but passed his daily health checks for two days before the mandatory testing.

One of those days was the day after the current cluster had been notified, and the day that Auckland went back into alert level 3.

He didn't have direct interaction with guests, and maintenance workers had appropriate personal protective equipment, Bloomfield said.

The man's household and workplace contacts who had been tested had earlier returned negative results.

"There are a number of casual contacts from a church service - 56 people have all had contact made except for two, and are in self-isolation and are being tested as well," Bloomfield said.

UNITE UNION

Unite Union general secretary Gerard Hehir yesterday said it was very important to drill down and find what happened with the mystery case at the Rydges Hotel in central Auckland.

In an interview on RNZ today, Hehir described communication between the Government and the Ministry of Health on the testing issue so far as less than ideal.

Hehir said it was particularly concerning no one has figured out what happened and how.

"Our members are mostly room attendants who clean the rooms in isolation facilities when guests leave, and this maintenance worker has obviously a similar pattern of work to them," Hehir said.

To be fair, he said, the isolation set-up was an extremely complex operation akin to a new prison system.

"This is going to go on for months and months and maybe years. We really need to get the processes down very clear, and testing needs to be done properly and efficiently," said Hehir.

He said his members who work alongside people with Covid want to know when they should be tested, saying they could be the "eyes and ears" of making sure the safety systems work.

Hehir said union members had expected to be tested, but haven't known how often they should be tested, nor did he know of any union members who have resisted being tested.

He said it was unclear for union members what happens if they do not have sick leave, particularly if they have run out or only started work and do not have sick leave.

Hehir said there must not be any disincentive for staff not feeling well or self-isolating if they had been tested or showed any symptoms.

"They are low wage workers. If they think they are going to lose money, then they are less likely to put their hands up and be tested or take a precautionary approach, which is what is needed," Hehir said.