A one-year-old child from the Hunter region is among 19 coronavirus cases identified overnight, the NSW Health Minister Brad Hazzard has confirmed.

Yesterday, health authorities conducted 24,640 COVID-19 tests — up 50 per cent from the previous week — and detected 19 cases across Sydney and Port Stephens.

Mr Hazzard confirmed one of the new cases was a toddler who attended the Goodstart Early learning centre in Anna Bay, which was closed today for contact tracing and cleaning.

While another case, he said, was a school-aged student who attended Tomaree Public School in Port Stephens.

The primary school and the nearby Tomaree High School were also closed today for deep cleaning.

The Hunter New England Local Health District also urged anyone who had symptoms and visited the Salamander Bay Village Woolworths on July 17 after 2:30pm to get tested.

Similar advice was extended to any person who visited the Fingal Bay Cafe and Takeaway between 11:30am and midday.

Mr Hazzard praised the enormous spike in testing figures across the state, noting 800 of the 24,640 cases were from Port Stephens, where the last cases were found.

“We all need to be on high alert and not complacent,” he said.

“We don’t want to end up in a situation where we have broadscale transmission.”

Both Mr Hazzard and the NSW Treasurer, Dominic Perrottet, urged the organisers of a planned Black Live Matters protest to reconsider the public demonstration.

“Now is not the right time to be on the streets and intermingling with each other,” Mr Hazzard.

The State Treasurer said there were “economic consequences” of “poor behaviour” and pointed to the adverse impact as a result of the second wave in Victoria.

Mr Perrottet said the lockdown in Melbourne was costing NSW about $1.3 billion a week.

The other confirmed cases include another three people associated with the Crossroads Hotel cluster in Casula, bringing the total count there to 56.

Another nine cases are linked to the Thai Rock restaurant in Wetherill Park, which now stands at 46 cases in its cluster.

NSW Health also said three cases were still under investigation, while another three were returned travellers in hotel quarantine and a fourth was a south-western Sydney resident self-isolating after arriving in NSW.