However, NSW Deputy Premier John Barilaro said he had a "lot of confidence" the Riverina could open up after September 10 when the statewide lockdown is due to end.

The Murrumbidgee Local Health District director public health Tracey Oakman said the Riverina had been fortunate given the virulence of the Delta strain.

"I think it's just a matter of time before we get COVID in our region and local cases," Ms Oakman said in Albury on Monday.

"It's a very infectious disease, Delta strain is something that transmits easily.

"We do have people travelling through all the time, essential workers.

"While there are precautions in place, where they do tests every three days, the weekend's example...just shows you how easy it is for a worker to travel through and be positive."

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Ms Oakman was referring to the revelation on Saturday that two truck drivers, who subsequently were found to have COVID on reaching Western Australia, stopped at Gundagai and Wagga last week.

Mr Barilaro told regional journalists on Monday that areas ripe for opening were those without cases.

"It's clear that in big parts of the state....the northern part of the state and the Riverina as well, I think there's a lot of confidence that you can open those large areas up and have minimal risk," he said.

Mr Barilaro then qualified his comment by saying it was too early to give particulars about the re-opening of regions and noted the Shepparton COVID cluster.

"What's happening across the border in Victoria, we'll keep an eye on that and that could play into that," he said.

The Nationals leader said any evaluation of which areas open was likely to occur early next week, with the lockdown due to end at midnight on Friday week.

Meanwhile, Ms Oakman lauded Wagga Trucks for its COVID plan in assisting the response to the discovery the two travelling drivers had been there for repairs last Wednesday.

"It's a really good lesson...so for businesses the better your COVID plan...the less people we need to isolate and identify as close contacts, so credit to that business," she said.

Ms Oakman also the ongoing testing of sewage, after positive fragments were found at Temora.

Albury's wastewater is being assessed each Tuesday, with the data analysed by a laboratory in Sydney before the results are presented to the local health district.

Fragments are shed up to four weeks after a COVID case, meaning a sufferer may have left town.