The warning came despite deputy premier John Barilaro and Northern Tablelands MP Adam Marshall both called for the lockdown to end in the region.

"There comes a time in my view where the 'health advice' cannot be the sole determinant of lockdowns and restrictions," Mr Marshall said.

"There's no doubt the health advice is critical, but this should be tempered by other considerations, such as impact on people's mental health and the local economy, especially the survival of small and medium sized businesses, which are the backbone of our country towns."

The health advice comes as across the Northern Tablelands the number of people getting tested for COVID-19 has dropped rapidly.

Sewage surveillance results will also be one of the factors used to decide which local government areas (LGAs) - if any - will come out of lockdown when it finishes this Friday.

Read also:

"What we will be looking at is how many active cases there are in a region and how many of them were actually in the community and infectious," Mr Barilaro said on Monday.

"If people have been in isolation and they've been in isolation for their period, that'll be discounted.

"We'll be looking at which LGAs are in close proximity to other LGAs that have got high numbers, so LGAs around Dubbo will be an area of concern. We'll be definitely looking at LGAs with sewage surveillance detection as well."

A crisis meeting will make a decision on regional NSW lockdown on Wednesday afternoon, which will be announced on Thursday.

Tamworth recorded its fourth mystery positive sewage test for COVID-19 in a row on Saturday, with additional test results due on Wednesday. With no known cases in the community, the source of the detection is unknown.

Saturday also saw Glen Innes record its first positive sewage test for COVID-19.

There are no known cases in either town.

Mr Barilaro has also indicated that some regions which stay in lockdown beyond September 10 will remain under stay-at-home orders until the state reaches its first 70 per cent adult vaccination target.

If the current pace of vaccination rollout continues, the state will reach the 70 per cent target on Monday, October 18, he said.

On Tuesday Mr Barilaro said he was pushing for large areas of regional NSW, which have had no cases during the recent Delta outbreak, to come out of lockdown this weekend.

He flagged an area of northern NSW - stretching from the northern rivers to New England - and the Riverina region to the south-west as the most likely to be released from lockdown, if that approach is taken.

"That's my hope, but I've got to get the support of Health to agree with that," he said.

He said if positive sewage tests could be traced to potential causes it would make it easier to put forward a case for those areas to come out of lockdown.

CLICK HERE TO RECEIVE EMAILS FEATURING THE BEST LOCAL NEWS AND STORIES, AS WELL AS OUR BREAKING NEWS ALERTS

But while COVID-19 positive sewage tests are on the rise across our region COVID-19 the testing rates in our communities are declining.

Last week testing rates were down about 50 percent on the week prior, and this week they are down again according to the statistics released by Hunter New England Health on Tuesday.

In Armidale the number of people getting tested for COVID-19 dropped by 25 percent compared to last week, in Glen Innes there were 20 percent less getting tested, in Tenterfield testing was down 55 percent, and in Moree 30 percent less people took the test.

But it was Inverell that dropped the most. where a whopping 65 percent less people were tested for COVID-19 compared to the week before.

As testing rates drop off, Hunter New England Health public health physician David Durrheim said now is not the time to become complacent and any symptoms should prompt testing and not just be passed off as spring allergies.

Local COVID-19 testing sites can be found here.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can access our trusted content: