New Zealand has suffered its first coronavirus case for more than two months, sparking a travel ban with Australia.
The more contagious South African mutant strain was discovered in a 56-year-old woman who had flown back from London after visiting Spain and the Netherlands.
She tested positive ten days after her mandatory 14-day quarantine ended.
New Zealand hasn't had a covid case since mid-November because it has a zero covid strategy of strict border controls. It has recorded just 25 coronavirus deaths.
The government hastily shutdown the country's travel-bubble with Australia for at least 72 hours while further contact-tracing is carried out.
COVID-19 Minister Chris Hipkins (pictured left with Prime Minister Jacinda Ardern) praised the woman for scrupulously keeping track of her movements
Security patrol outside the Pullman Hotel in Auckland, New Zealand, earlier this year. The woman had been staying at the hotel for 14 days and tested positive after leaving
'The strain of infection is the South African variant and the source of infection is highly likely to be a fellow returnee,' said Health Minister Chris Hipkins.
Australian Health Minister Greg Hunt said it was a case of 'significant concern' and the increased possibility of transmission had prompted his government to suspend its 'travel bubble' with New Zealand for a minimum of 72 hours.
'This will be done out of an abundance of caution whilst more is learnt about the event and the case,' he told reporters in Canberra.
'The changes come into effect immediately.'
Hunt urged New Zealanders with a flight to Australia scheduled within the next three days to 'reconsider their need to travel' as they will have to go into hotel quarantine - like other international arrivals - for up to 14 days on arrival.
The woman is thought to have been infected during quarantine by a person on the same floor of the hotel who tested positive two days before the woman left.
The 56-year-old travelled around the Northland region near Auckland after her release from quarantine and showed symptoms for several days before being tested.
Two people close to her, including her husband, have since returned negative tests and New Zealand's director-general of health Ashley Bloomfield said they likely avoided contracting the illness due to the type of infection.
'She didn't talk about respiratory symptoms, it was more muscle aches, so she may not have been sharing or spreading the virus much,' he said.
'I don't think that's peculiar to this variant, it's just how it was expressed in this woman.'
The World Health Organization has said there is no clear evidence the South African variant leads to more severe disease or a higher death rate.
People wait in line outside a pop up Covid-19 testing station in Auckland in November
New Zeland's Health Minister Hipkins said: 'This woman concerned has been scrupulous in keeping a good record of her movements, scanning the QR codes wherever she has gone.
'That's laid a very good foundation for our contact tracing team ... I want to acknowledge that.'
Health authorities have also ordered further testing at the woman's isolation hotel, the Auckland-based Pullman Hotel.
While the case is the first in the community for three months, New Zealand has continued to pick up cases within the border regime, including the British mutant strain.
The country's total number of confirmed cases is 1927, with 25 deaths recorded since the disease arrived on Kiwi soil in February last year.
South African Covid mutation poses 're-infection risk' which could overpower vaccines, study finds
The South African coronavirus mutation poses a 'significant re-infection risk' and could overpower vaccines, new research has found.
The strains discovered in Britain, South Africa and Brazil all have mutations of a spike protein, which enables the virus to latch onto human cells and therefore plays a key role in driving infections.
But it is one mutation in particular - known as E484K and present in the variants from South Africa and Brazil - that has experts worried about immunity 'escape'.
Researchers in South Africa tested the variant found there - called 501Y.V2 - against blood plasma from recovered Covid-19 patients.
They found it was resistant to neutralising antibodies built up from prior infection, meaning that it could also defy immunity provided by jabs.
'Here we show that the 501Y.V2 lineage, which contains nine spike mutations and rapidly emerged in S.A. during the second half of 2020, is largely resistant to neutralising antibodies elicited by infection with previously circulating lineages,' the authors said.
'This suggests that, despite the many people who have already been infected with SARS-CoV-2 globally and are presumed to have accumulated some level of immunity, new variants such as 501Y.V2 pose a significant re-infection risk.'
The researchers added that this might also affect the use of convalescent plasma as a treatment for Covid-19.
They also referred to 'implications' for vaccines developed based on immune responses to the virus's spike protein.