There is one new Covid case at the border in New Zealand, director general of health Ashley Bloomfield says.

Today's new case is a woman in her 30s who arrived from Dubai on September 9 and is in managed isolation. She is linked to the three border cases announced yesterday.

It emerged this afternoon Nigel Te Hiko had died in Waikato Hospital, nearly two weeks after his brother Alan died in Auckland from the virus.

Nigel, 54, is believed to have contracted Covid from Alan, who had worked at the Americold facility in Auckland.

He is the 25th New Zealander to die of Covid-19 and the youngest.

Bloomfield said Te Hiko's family had a message for New Zealanders:

"The man's whanau has asked us to tell the country that coronavirus is so real and to be vigilant and cautious.

"They have issued a plea to all New Zealanders: If you are sick and have symptoms stay home and seek advice about getting a test," Bloomfield said.

Bloomfield said the man's death highlighted the seriousness of Covid-19 and said his thoughts were with Te Hiko's family.

"Ngāti Raukawa has lost clearly a rangitira...they mourn the loss of their loved one.

• Covid death: Kiwi family lose second loved one to coronavirus

"I can't imagine how devastating this is for this whanau," Bloomfield said.

He said the death was another reminder of how dangerous the virus was, especially for those with pre-existing conditions.

Nigel lived in Tokoroa and had been visited by his brother before Auckland's August lockdown.

The deaths that we've seen in the Te Hiko family just do re-iterate just how deadly this virus is, he said. The death rate in New Zealand was between 1 and 2 per cent of the country's confirmed cases.

The healthcare worker with Covid

The exact epidemiological link to the health care worker who tested positive at the Auckland quarantine facility has been confirmed.

The worker went into the room to care for a person who tested positive and required hospitalisation.

All close and casual contacts from the gym whose test results have been returned have tested negative.

Bloomfield said there was very strict requirements and enforcement around the use of PPE at the facility where the healthcare worker contracted Covid-19. He said a clinical review would establish how she contracted it.

"We're increasingly confident we have ring-fenced the cluster and sub-cluster," he said.

There was also no indication anyone had contracted it from the healthcare worker. He said amber-green was the best way to characterize his feeling on the current situation.

Yesterday there were no new cases in the community with the three confirmed cases being in managed isolation facilities at the border.

The three cases were a man in his 30s and two children who arrived together from Dubai on September 9. They have been in managed isolation at the Ibis Hotel in Rotorua and tested positive for Covid-19 during routine testing around day three of their stay.

There were four people in hospital with Covid-19 – one was in isolation on a ward in Auckland City Hospital, and one was in isolation on a ward in Middlemore. Two were in ICU, at North Shore and Waikato hospitals.