Towns face isolation as NSW floods persist

After months of flooding in NSW's central west, Condobolin residents are about to confront their highest river levels in 70 years.

"The area is already in widespread flood ... Everywhere you look, there is water, water, water," Lachlan Shire Mayor John Medcalf told AAP.

"Mother Nature doesn't seem to want to stop putting water out of the sky."

Many residents in the agricultural part of town have been cut off for months, the mayor said.

The flood peak that caused major flooding in Forbes over the weekend is expected to pass Condobolin on Monday, potentially reaching 7.3 metres - just below the 7.4 metres recorded during the 1952 floods.

Mr Medcalf said those on farms would be isolated for longer, while the entire town faces being cut off if the main road is impacted.

The population of 3500 can rely on its airport for supplies, but Mr Medcalf urged those who require medical attention in Forbes to come forward so they can make arrangements in case floodwaters cut off the town.

"We have 4500 kilometres of road within our shire. And I'd say every road in the shire is impacted."

SES volunteers continue to help town residents with sandbagging, door knocking, resupply, and livestock movement, as the agency prepares to bring in more resources.

As floodwaters recede in Forbes, several towns including Walgett, Lightning Ridge and Collarenebri remain isolated.

"SES will be working with these isolated communities to ensure they have regular resupply drops and support," the agency said.

The SES received more than 290 calls for assistance in the past 24 hours, including 10 for flood rescues.

In Forbes, at least 400 homes and businesses have been impacted by recent flooding, NSW Emergency Services Minister Steph Cooke said.

The town's evacuation centres have accommodated more than 135 groups of people ranging from single residents, single families, the elderly and those rescued from floodwaters, Resilience NSW confirmed to AAP on Tuesday.

Tuesday marked the 56th consecutive day of the current flood event, Ms Cooke said.

"It's understandable that flood fatigue and complacency would be a very real risk not just for our volunteers and our staff, who have been ceaseless in their efforts, but also for our communities," she said.

Flooding has again wrought damage to regional roads.

"Our biggest problem is, we've been in flood for four months, so our road network has washed away," Forbes mayor Phyllis Miller said.

Local Government NSW declared a statewide roads emergency last week due to flood damage, saying it will require state and federal funding to fix.

In parliament, NSW Premier Dominic Perrottet acknowledged the damage flooding caused on regional roads, promising to work with councils and the federal government to restore the infrastructure.

"We know the next fire will come, the next flood will come, and that investment is crucial to the lifeblood of those regional communities," he said.

Meanwhile, residents in Bathurst, Oberon, Wallerawang and Lithgow remain without gas after flooding damaged a pipeline running under the Macquarie River last week.

Energy infrastructure company APA Group, which owns the pipeline, is continuing its work on temporary solutions to restore supply.

About 75 per cent of Bathurst had been reconnected by Tuesday afternoon.

A tanker is expected to arrive on Friday, feeding gas into temporary pipes that would allow Oberon, Lithgow and Wallerawang properties to reconnect over the course of a week.

APA anticipates full permanent gas supply returning by early December, depending on the weather.