E tū head of aviation Savage said the woman had not been to NSW in the past three weeks but had visited two Covid-infected countries since the start of August, including Japan.
The union for cabin crew, E tū was informed late on Wednesday that an Air New Zealand 787 crew member tested positive during routine surveillance testing.
"787 cabin crew, in particular, are at the forefront of bringing New Zealanders home and keeping vital passenger and cargo routes open. They make a lot of sacrifices in terms of their personal freedoms so that Kiwis can stay connected," Savage said.
A wider group of cabin crew are also affected because they crewed on the same flights as the person who tested positive. E tū members on the ground may also be considered close contacts.
All affected crew and workers are being removed from rostered duties and are under Ministry of Health instructions to isolate until they are tested and cleared.
"At times like this, cabin crew rally around to support their fellow crew members. The 787 welfare committee will also do what they can do assist," Savage said.
The airline was working with the Ministry of Health to identify if any other New Zealanders have come into contact with the crew member.
Air NZ was approached today about how many close contacts the woman has, but Johnston said they couldn't comment.
However, he said she was "one of our most experienced aircrew".
"All of our crew have been diligently following the protocols in place for operating to international destinations, which are set out by the Ministry of Health.
"These include taking private transport to and from their layover hotel, isolating in the hotel and wearing PPE at all times while on layover. Aircrew are also subject to regular surveillance testing where they are tested up to once every seven days.
"Our aircrew feel a strong sense of shared responsibility towards protecting New Zealand's borders and they continue to do a fantastic job."
She was fully vaccinated, Johnston said.
The fully vaccinated crew member tested positive on Wednesday, August 18, as part of the airline's regular surveillance testing programme for international aircrew.
She was not part of the community cluster of positive cases, which this afternoon numbered 21.
"There are significant precautions in place for our crew operating to international destinations set out by the Ministry of Health, and we are confident our people are following the protocols diligently.
Johnston said 82 per cent of Air NZ frontline workers had at least one dose of the Covid-19 vaccine and 80 per cent were fully vaccinated.