There are four new cases of Covid-19 reported in New Zealand today, all in managed isolation.
In a statement, the Health Ministry said it was also investigating one suspected historical case, which was not included in today's numbers.
The imported cases were one person arrived from the Philippines via Hong Kong on 3 October and tested positive on day 12 of their stay at a managed isolation facility in Auckland; one who arrived from Peru via Mexico and the USA on 10 October and was taken to a managed isolation facility in Christchurch; and two people who arrived in Auckland from Hong Kong on 11 October.
The Ministry said the investigation into the possible historical case was launched after someone returned a weak positive result.
"This individual is a recent returnee from the United States and completed their full 14 days in a MIQ facility in September. They were asymptomatic during their time in MIQ and returned two negative tests during this time. They were released from MIQ on September 21.
"After becoming unwell this week, they sought medical care. They were subsequently tested for Covid-19, which has returned a weak positive result, indicating an old infection. We have undertaken further testing today to fully confirm this is a historic infection."
The Ministry said a test conducted today had returned a negative result, which "strongly suggested" that this was a historical infection.
"We are taking precautionary measures as we always do in these instances and the individual has been transferred to an MIQ facility in Wellington.
"As we have seen with other cases, individuals can return weak positive tests if they have been infected earlier in the year. This case follows a typical pattern of what we have seen in other historical cases.
"These cases can emerge after the person has a respiratory illness that is not Covid-19, such as a cold or influenza. Residual remnants of the virus can be picked up through swabbing, with inflammation often bringing forward virus particles that were not previously picked up."
Further details about the suspected historical case are expected to be released later today.
New Zealand now has a total of 1524 confirmed cases of the coronavirus.
The total number of active cases is 46 - all imported cases. There are no active community cases of Covid-19.
There were 5078 tests processed yesterday.
Yesterday, the Ministry of Health reported two new cases, both in managed isolation, and all active cases in the country were imported ones.
Overseas, Covid-19 has reached the campaign of US Democratic vice presidential nominee Kamala Harris, who cancelled travel plans as a precaution after one of her staff members tested positive. In further steps in the UK to grapple with a surge in cases, London is to go into a tighter lockdown.
- If you have symptoms of the coronavirus, call the NZ Covid-19 Healthline on 0800 358 5453 (+64 9 358 5453 for international SIMs) or call your GP - don't show up at a medical centre