Ashley Bloomfield says our Covid Delta outbreak has grown to a total of 21 in the community - with 11 more today.

Two people are in hospital with covid - one in their 20s and one in their 40s ... and are stable

All other cases are being put in quarantine, or are there already.

Eight cases are being investigated and aren't formally linked, but likely are part of the cluster.

Three new cases in MIQ have meant people in their cohort need to stay in longer.

An Air New Zealand staff member with Covid is considered a border case, and not linked.

Prime Minister Jacinda Ardern says contact tracing has showed the cases came into our community, from the New South Wales outbreak'

Sequencing shows our current cases are strongly linked to a person who flew here from Sydney on August 7, who went into MIQ, then quarantine - and was transferred to Middlemore Hospital when they fell sick.

It's likely the virus arrived on August 7, and was therefore likely in the community for a relatively short time - on the balance of evidence.

Staff at the Crowne Plaza, and Jet Park and transporters of returnees and MIQ clients are being investigated.

Only one Crowne Plaza staffer was slightly behind on testing, and two at Jet Park.

Middlemore Hospital is not considered a likely source of the outbreak.

Covid -19 modeller Professor Shaun Hendy joined Simon Barnett and James Daniels to unpack today's news.

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