10 new coronavirus cases in NSW - six returned travellers and four from known case or cluster

They include six returned overseas travellers, who are in hotel quarantine, and four locally acquired and linked to a known case or cluster.

It was another good day for test numbers, with 22,805 people presenting.

NSW Health also reported an additional 27,135 historic tests from a private laboratory, all of which were negative.

The latest numbers were revealed as Premier Gladys Berejiklian and Health Minister Brad Hazzard welcomed Chief Scientist Alan Finkel and a delegation of Victorian officials, who are in Sydney to look at what Prime Minister Scott Morrison described as the "gold standard" in contact tracing.

NSW Health officials joined their Victorian counterparts in the meeting at the COVID-19 operations centre in the Rural Fire Service headquarters at Homebush.