Some areas recorded up to 200 millimetres, while the Illawarra and South Coast region State Emergency Services received 60 calls for help across the two days.

One was to a heavily pregnant woman who was rescued from her confined property, Incident controller Tom Jory said.

At least 21 people were isolated in a camp group near Moruya on Tuesday night.

"We have been in contact with them, and they are safe and well," Mr Jory said.

"We have deployed special operations paramedics and our specialist flood rescue volunteers to Batemans Bay to support any actions required for the campers overnight."

Bega was among the South Coast's worst affected areas, which saw widespread flooding and road closures after the Bega river peaked at 5.63 metres on Tuesday morning.

Bega Police chief inspector Anthony Moody said some roads remained closed overnight and some had reopened as water continued subsiding.

A low level flood warning remained in place in the area on Tuesday night.

Mountain ranges shielded Canberra from the worst of the wet weather, where just up to 20 millimetres fell across the two days.

Bureau of Meteorology forecaster Rebecca Kamitakahara said showers would continue on Wednesday and clear as the weekend approached.

"There is the chance of a couple of millimetres in Canberra tomorrow at most," Ms Kamitakahara said.

"It is beginning to warm up too, with [temperatures in the] low thirties [expected] over the weekend."

However, drivers travelling to or from the South Coast were urged to exercise caution and reduce speed along the Snowy Mountains highway, after a landslide on Brown Mountain closed an east-bound lane.

"A geotechnical engineer is carrying out a further assessment to determine repairs required and staff remain on site," a Roads and Maritime Services spokesperson said on Tuesday.

Further down the coast, a man who became stuck while attempting to drive over a flooded bridge on Monday afternoon was fined for negligent driving.

The 45-year-old man was rescued by police and the occupants of a passing Landcruiser after he tried to drive through 1.4 metre flood waters on the Murrah Bridge, between Tathra and Bermagui.

The driver was unharmed and his black Ford Territory was retrieved undamaged but he copped a $425 fine.

The following day, another driver became stuck while attempting to cross a creek in the flooded Dignams Creek area near Batemans Bay.

The abandoned car prompted a helicopter search before he was found at his friend's place that was also cut off by floodwaters.

These incidents have prompted police to remind people to avoid driving, walking or riding through flooded waters.

"It is extremely dangerous as fast moving under currents can quickly wash people and vehicles away," Inspector Moody said.

"Whilst it may look safe on top, you can never underestimate what can be happening underneath."

The heavy rain began to ease on Tuesday across the South Coast, Southern Tablelands, Snowy Mountains and Illawarra, hydrologist with the Bureau's Flood Warning Centre, Hugh Bruist, said

Up to 60 millimetres was forecast overnight for some areas.

The focus had shifted to the central and northern parts of the NSW coast.

"We are concerned about Wyong, Newcastle and surrounding areas," Mr Bruist said.

Severe weather warnings were put in place for the mid north coast and Hunter districts, to remain in place overnight.