Auckland’s three-day lockdown will begin on Sunday night, while the rest of the country is also placed under heightened restrictions, amid fears that a more contagious strain could be involved.

The lockdown will be the first the country has seen in six months.

New Zealand’s Covid-19 minister Chris Hipkins confirmed that a family-of-three, from south Auckland, had tested positive for the disease but that the cases are being treated as unexplained. He also said authorities were tracing people the family had been in contact with.

Prime Minister Jacinda Ardern has returned to Wellington after being set to attend a gay pride event in Auckland. Instead, she will now hold discussions on next steps from the country’s capital.

She announced the move for Auckland after an urgent meeting with other top politicians in the cabinet.

Ms Ardern said they decided to take a cautious approach until they found out more about the outbreak, including whether the infections were of the more contagious variants.

Prime Minister Jacinda Ardern returned to Wellington to be briefed on the new cases

The patients’ places of work and the daughter’s high school have taken steps to stop any further spread of the disease.

It comes after January saw the country’s first coronavirus case in more than two months, when a 56-year-old woman returned from Europe.

New Zealand has been hailed around the world for its success in dealing with the virus and pushing case and death rates down to virtually zero.

People have returned to work, while sporting events and concerts are going ahead without masks or social distancing measures.

The country is set to start vaccinating its population of 5 million on February 20, after receiving their stock of Pfizer vaccines earlier than expected.

At a press conference on Sunday Ms Arden said: ‘I’m asking New Zealanders to continue to be strong and to be kind.

New Zealand has enjoyed almost no local coronavirus restrictions for months

‘I know we all feel the same way when this happens. We all get that sense of “not again”.

‘But remember, we have been here before and that means we know how to get out of this again, and that is together.’

Although all travellers returning to New Zealand have to quarantine for two weeks, the virus has made its way through the quarantine system on a few occasions.

Officials are still investigating whether this is what happened in the latest outbreak.

Mr Hipkins said: ‘New Zealand has kept Covid-19 contained better than almost any other country. But as we have kept saying, there is no such thing as no risk.’