- text by Candace Sutton, news.com.au

A breakthrough in understanding New Zealand's new Covid-19 outbreak has only deepened the mystery over its origins.

New Zealand scientists have identified the "family" of its latest Covid-19 outbreak and have revealed that its name is "B.1.1.1." and can be tracked all the way back to Wuhan.

The lineage of the genome sequence of the original cluster – which began as four new cases on August 11 and has grown to 30 – is also linked to cases in Australia.

Director-general of health Dr Ashley Bloomfield said the samples had "strong links" to the genomes of coronavirus in United Kingdom and Australia.

And B.1.1.1 is also present in countries including Peru, Uruguay, South Africa, Switzerland and Bangladesh.

But B.1.1.1. has no links whatsoever with the genomes of Covid-19 cases in the US.

The scientist who did the sequencing of B.1.1.1. told news.com.au that a sample from each positive Covid-19 test in New Zealand is compared with genomes from others around the world.

Dr Jemma Geoghegan, an evolutionary biologist and virologist at Otago University, said samples were sent to NZ's scientific research institute, ESR, to be read and analysed.

"We then compare the genomes with others from around the world and determine which genetic lineage they belong to.

"The new cases in New Zealand belonged to a lineage called B.1.1.1."

However, despite being able to identify the genome family of its latest outbreak, New Zealand has not yet been able to determine how the cases got into the country.

B.1.1.1. is not the genome sequence for any coronavirus case in managed quarantine, so the source of the new cluster remains a mystery.

After 102 days with no new cases, New Zealand's hopes of eradication and its worldwide reputation as a virus beater were dashed on Tuesday.

This was three days after four members of one family checked in to a hotel and visited a restaurant in the North Island tourist town of Rotorua.

The following day the family visited a Rotorua cafe, supermarket and the Skyline Gondola, and on Monday four other locations.

Last Tuesday afternoon, the first positive test result from a member of the family came back and within 90 minutes NZ Prime Minister Jacinda Ardern was informed.

AT 9.15pm she held a press conferencing announcing New Zealand had four new coronavirus cases and that Auckland would move into stage 3 lockdown and the rest of the country stage 2.

The restrictions were set to last until midnight on Friday but the government extended the lockdown for another 12 days as the cluster ballooned to 30 virus cases.

New Zealand has recorded a total of 1,602 coronavirus cases and 22 fatalities.