The Ministry of Health says it is "fully investigating" the circumstances surrounding a woman who tested positive for Covid-19 after flying from Auckland to Sydney last week.
The woman who flew out of New Zealand on July 20 is in a government-managed isolation facility in Australia.
"We will continue to fully investigate the circumstances of this positive result, including travel history," the ministry said in a statement today.
The ministry, which is following up household and other contacts of the woman, believes she may have been a previously unconfirmed case from March and this is likely to have led to the positive test result.
The woman who talked to the NZ Herald from her hotel isolation room in Australia says she is feeling "perfectly fine".
"I'm just very healthy and very lucky to be honest. I think people need to be aware that there are different cases out there and you can be asymptomatic and still be positive," she told the NZ Herald.
The woman is the third person in recent weeks to test positive after travelling from New Zealand.
Two transit cases
On July 6 a woman who transited through Auckland from Los Angeles on her way to Sydney returned a positive test in Australia. She did not leave the airport in New Zealand.
"At this point, there are not considered to be any close contacts who need to be traced or tested but enquiries continue with both the airline and airport," the ministry said in its statement today.
Then on July 24 a man who arrived in South Korea from New Zealand also tested positive. The ministry has said South Korean health authorities believe the person was infected during transit in Singapore.
"There continues to be no evidence of any transmission in New Zealand involving the traveller who tested positive for Covid-19 on arrival in South Korea," the ministry said in its update today.
"All domestic contacts of this case tested to date have returned negative results.
"While these results reinforce that the public health risk from this case continues to be low, further contact tracing is taking place around their travel within New Zealand, including their visit to the Queenstown area in early July, the South Auckland area where they were based and Christchurch where they departed from."