New Zealand scrambles to trace cluster

Lines of cars wrapped around the block for testing at pop-up clinics on Thursday (August 13) in New Zealand, as officials scrambled to trace the source of a new outbreak of 14 cases of the coronavirus.

Earlier this week -- New Zealand was the envy of the world, with zero cases of the coronavirus for more than three months.

But now Prime Minister Jacinda Ardern has switched gears; tightened restrictions and renewed a lockdown in the country's biggest city.

"It is being dealt with in an urgent but calm and methodical way. As we all learnt from our first experience with COVID, once you identify a cluster, it grows before it slows. We should expect that to be the case here."

Two days ago, the discovery of four infected family members in Auckland shocked the country, and raised some criticism of the government's handling of the virus.

Then on Thursday, 13 news cases were identified that linked back to the infected family -- through work or broader family connections.

The fourteenth case - was an overseas arrival in quarantine that also tested positive.

Ardern said it was a good sign that all the new 13 cases were linked back to the infected family and were being transferred to quarantine too.

Movement restrictions have been tighted in Auckland and social distancing measures have come back into action for the rest of the country.

Meanwhile the race to locate patient zero is on.

The country's top health expert, Ashley Bloomfield raised the possibility on Wednesday that the virus had first arrived via freight, given one of the infected family members works in a storage facility that deals with imported frozen goods.

But he later said it was more likely spread through people, rather than objects which are likely to carry infections:

"The most likely explanation is person to person transmission or more fleeting fomite transmission, then an infected surface somewhere."

But other experts suggested it was more likely the virus had been quietly spreading in Auckland for weeks.