A pregnant woman whose waters had broken was ferried through floodwaters by emergency responders after rising rivers cut a NSW town in two.
Forbes in the NSW central west was bracing for the overflowing Lachlan River to rise to a possible peak of 10.7 metres on Saturday, the highest level in 70 years.
The river was sitting at 10.66 metres at Forbes at 4pm on Saturday, and the major flood peak was forecast to pass through Cottons Weir during the evening.
About 500 homes were subject to evacuation orders as northern areas were cut off from the town centre and south.
The State Emergency Service received more than 200 calls for help and performed 10 flood rescues in the 24 hours to Saturday morning.
They included a call for help on Friday for a pregnant woman whose waters had broken.
SES volunteer Ryan Jones, who performed the rescue, said the woman was cut off by floodwaters in north Forbes and she needed help crossing the inundated roads to get to hospital with her midwife.
"The water was too deep and dangerous for private vehicles, so the only way for us to access this patient was via use of our high-clearance vehicles," he said.
Another person was rescued from their car after being trapped by rising waters near the centre of town.
Premier Dominic Perrottet said 50 Australian Defence Force personnel would be deployed in Forbes and about 200 troops would be made available for flooded communities across the state.
Major rivers across western and southern NSW were flooding, including the Murrumbidgee at Wagga Wagga, the Murray at Moama and the Lachlan.
Lightning Ridge, Collarenebri and Walgett in the state's northwest were all isolated by floodwaters.
The Namoi River at Wee Waa on the New England region's north-western slopes was expected to rise to a peak of 7.3 metres on Sunday, and authorities expected it to peak at 7.8 metres at Goangra on November 12.
Major flooding was also expected to continue at Warren on the Macquarie River for a few more days.
Water levels at Wagga Wagga, the largest inland town in NSW, peaked at 9.72 metres on Friday, the highest in more than a decade.
Emergency Services Minister Steph Cooke said on Saturday the floodwaters affecting Wagga Wagga and Forbes were moving downstream and risks of major floods remained for several communities.
"While we are experiencing a reprieve in the weather and, in fact, it's lovely to see some blue skies, the risk has not abated in relation to the amount of water in our river systems, passing through our communities and impacting on our lives," she said.
The SES has repeatedly warned people in inland areas of the dangers from so-called "blue-sky floods", during which rivers can rise to high levels despite rain no longer falling.
Around 20,000 residents in central-west NSW could be left without gas for a month after flood damaged a crucial pipeline.
The pipeline's operator, APA Group, said gas would be restored to houses and businesses in Bathurst over the next two weeks, while residents in Lithgow, Wallerawang and Lithgow might have to wait four weeks.
Across the border in Victoria, more than 40 flood hazard warnings were active on Saturday evening and hundreds of roads remained closed.
Major flood warnings were in place for the Murray River, and authorities warned those in Kenley in the rural city of Swan Hill should immediately evacuate.
Major flooding was expected at Kenley overnight on Saturday, with floodwaters expected to continue rising to their peak over the coming week.
Water levels at Mildura are expected to continue rising throughout November before a possible high in December.
Along the Murray River at Echuca and Moama, major flooding was expected to continue into next week although water levels were falling.