The current cases of Covid-19 in New Zealand have been linked to an Australian case who was taken to Middlemore Hospital earlier this week.

Prime Minister Jacinda Ardern and Director-General of Health Dr Ashley Bloomfield are providing a Covid-19 update on day two of the nationwide lockdown.

Ardern said the current positive cases have been linked via genome sequencing to a traveller who arrived from NSW on a managed red zone flight. That person returned a positive day one test on 9 August and was transferred to Middlemore Hospital on 16 August.

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She said the period in which cases were in the community was relatively short, but new information could change this conclusion.

Ardern said primary lines of investigation are staff at the Crown Plaza, staff at the Jet Park facility and staff involved in their arrival and transport. Middlemore Hospital is not part of the investigation.

Customs are investigating footage and identifying areas of interest and testing staff.

“Nothing has eventuated from this line of inquiry to date.”

Staff at Jet Park and Crown Plaza are being retested.

Earlier today, Dr Bloomfield said health officials will be preparing a paper for Cabinet to consider tomorrow regarding the timing of the level 4 lockdown which is currently at least three days around the country and at least seven days in Auckland and Coromandel.

“Our aim of course would be to have as short as possible lockdown but it’s so important in this situation, we’ve seen that from the different outcomes in different states in Australia, that … you go into lockdown type arrangements quickly and you don’t lift them too early.”

And Covid-19 modeller Professor Shaun Hendy told Morning Report he is reasonably confident that the strict level 4 lockdown will be able to control an outbreak of the Delta variant, but warns that Auckland is likely to be in lockdown for longer than seven days.