The positive Covid-19 case that travelled to Wellington from Sydney has been confirmed as having the more infectious Delta Covid-19 variant.
New South Wales health authorities have issued a media release after 9pm on Friday confirming the positive Covid-19 individual who visited Wellington as having the highly infectious variant first found in India.
"The confirmed case that travelled to New Zealand is linked to the Bondi cluster, which has been confirmed as the Delta Covid-19 variant," a NSW Health spokesperson said.
"The person accompanying the confirmed case of Covid-19 who travelled to New Zealand from Sydney, tested negative on return to Australia and was not infectious while in New Zealand."
Wellington is into its third day at level 2, which remains in force until 11.59pm on Sunday, following no positive results after thousands of tests across the region.
At 10:31pm on Friday, the New Zealand Ministry of Health followed with their own statement confirming the Australian tourist who visited Wellington had the Delta variant.
The Ministry said they are awaiting confirmation of the completion of whole genome sequencing after New South Wales health officials this evening confirmed an epidemiological link to the Delta variant.
Director of Public Health Dr Caroline McElnay said the confirmation reinforces the Government's precautionary approach with the Australian Covid-19 positive traveller to Wellington.
"The signs so far are encouraging – testing has ramped up and there have not been any community cases at this point," McElnay said.
"But I want to emphasise the importance of staying vigilant, stay home if unwell and get advice about having a test, wash hands regularly, cough and sneeze into the elbow, wear masks or face coverings on all public transport, and keep track of where you've been – scan QR codes wherever you go and turn on Bluetooth tracing in the app dashboard.
"It's incredibly important people keep up to date with the Ministry's locations of interest in Wellington and if you've been at one, to continue to isolate either for the full 14 days and get at least two negative test results or to isolate until a negative day five test, depending on your situation."
Earlier on Friday, NSW Premier Gladys Berejiklian announced large parts of Sydney are heading into a lockdown, with a stay-at-home order lasting until midnight next Friday.
NSW has recorded its biggest rise in daily Covid-19 cases since this latest outbreak began, with 22 new locally acquired infections.
These areas include Woollahra, Randwick, Waverley and the City of Sydney.
Some have warned Sydneysiders are "sitting ducks" as the Delta variant spreads, but others argue the number of "mystery cases" does not yet warrant such drastic action.
The NSW Government has been criticised for resisting calls to lock down the city despite another rise in cases on Thursday, bringing the latest outbreak to 48.
Premier Berejiklian said it was "perhaps the scariest period" that the state had faced since the start of the pandemic due to the new Delta variant – but insisted that the tough restrictions announced on Wednesday were the "appropriate settings".
Warnings have been issued to Australians over the highly infectious Delta strain with one epidemiologist describing positive cases are "walking into a cloud of infectious particles".
Mary-Louise McLaws, professor of epidemiology at the University of New South Wales and an adviser to the World Health Organisation, described the spike in numbers as "enormous" and said the Delta strain is mutating like never seen before.
While McLaws praised the decision on masks, she revealed some terrifying realities of the new variant which has the world watching over the "fleeting" manner in which the virus is spreading.
Talking to the ABC's Gemma Veness, McLaws said the variant means people become more infectious earlier than that of its virus predecessor, which backs research from Chinese doctors who say that up to 12 per cent of patients are becoming severely or critically ill within three to four days of the onset of symptoms.
In the past, the proportion had been only 2 or 3 per cent of those infected.
"This variant of concern means that you can start to become more infectious to people earlier on, so we know that you're very infectious with any variant or wild strain at about day 5 when you become symptomatic but certainly from day 3 onwards you can of course still infect people," McLaws said.
"With this particular Delta it looks as if you are very much more infectious."