Woman critical after NSW flood rescue

An elderly woman is fighting for her life after being rescued from flood waters in the NSW Hunter region.

The woman is one of two people who had been reported missing near Stroud, about an hour north of Newcastle, on Tuesday morning.

SES deputy commissioner Steven Pearce said the elderly couple had been located.

"They have been rescued and taken to hospital," he told Seven Network.

"My information is that the lady is in critical condition."

Mobile phone contact was made with the missing couple earlier on Tuesday before the phone battery apparently died.

Gale-force winds hampered the rescue mission as helicopters were unable to be used.

Mr Pearce said at least 20 people had already been rescued and there were still numerous people caught in dangerous situations.

"We have multiple rescues going on at the moment where people ... are stranded in floodwaters, attempting to drive through floodwaters. Other people have attempted to drive through causeways and been washed over causeways," he told ABC television.

"We have really grave fears for some of those people and we're doing everything we can to address that."

The east-coast low is one of the worst the state has experienced in the past two or three years, he said.

There are flood watches on every major river system in the NSW Hunter and mid north coast area.

"Rainfall is anywhere between 100 and 200mm of rain in some areas," Mr Pearce said.