The state recorded more than 340 cases of community transmission to 8pm Tuesday, and carried out 119,000 tests, premier Gladys Berejiklian announced at the Wednesday morning update.

The slightly lower case numbers came a day after the state's record high of 356.

"We had 344 cases to 8pm last night of community transmission, at least 65 of those were infectious in the community for all or most of their infectious period," Ms Berejiklian said, acknowledging that detections remain high.

"We expect that to continue but positively we are starting to see a decline in cases in the Fairfeld local government area and the Canterbury-Bankstown local government area.

Two more people have died with the Delta strain, a woman in her 80s and a man in his 30s who had underlying conditions, Ms Berejiklian said.

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The Dubbo lockdown comes into effect at 1pm after days of warnings and increased testing following the detection of virus fragments in sewage surveillance.

"As had been foreshadowed, in Dubbo there were two cases," Ms Berejiklian said, adding that community's leaders had been informd.

"My final message today ...is please come forward and get vaccinated. We have passed 4.5 million jabs, we have a target of six million jabs by the end of August."

Positively, the Riverina vaccination hub in Wagga had its busiest day yet on Monday, as federal health statistics reveal one-fifth of the region's residents are now fully-vaccinated against the virus.

The Department of Education confirmed it had been contacted by NSW Health about a positive case at Dubbo West Primary School, and students and staff at Macquarie Anglican Grammar School have been told to stay at home after a student was identified as a close COVID-19 contact.

Dubbo MP Dugald Saunders said the positive case was isolating at home after becoming symptomatic on Monday and being tested on Tuesday. Nine close contacts had been identified so far and it is not yet known how transmission occurred, he said.

The cases are a woman aged in her 40s and a young child, chief health officer Kerry Chant announced on Wednesday morning.

The Hunter New England Local Health District has confirmed another 14 cases - seven in Newcastle, six in Lake Macquarie and one in Maitland - and it is looking unlikely that region will emerge from lockdown this week as planned, Ms Berejiklian said.

The seepage of COVID-19 into the regions has Wagga leaders on edge, and police have revealed the flimsy excuses Sydneysiders have been trotting out when trying to sneak into the city.

Riverina Police District Superintendent Bob Noble said officers continue to catch out people flouting the rules and 34 infringement notices have been handed out since July 13.

"Flimsy excuses will not be accepted," he said.

"They better be able to substantiate that they are here for a valid, bona fide reason and not something they have just concocted."

As regional areas such as Tamworth and Byron Bay - now joined by Dubbo - go into snap lockdowns, Superintendent Noble said Riverina residents would notice a more visible police presence.

Testing wait times are also frustrating Wagga residents, with reports of days-long waits between swab and results from particular sites prompting the question of why more regional labs aren't established to cope with demand.

Investigations are being carried out by Charles Sturt University after several students were fined and inquiries into the identities of up to 40 people continue after an illegal party was held at the Wagga campus.

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"Charles Sturt is extremely disappointed in the actions of these students, especially given the extensive measures the university has implemented to respond to COVID-19 and the ongoing impacts of the pandemic," interim vice-chancellor John Germov said.

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