Wild weather lashes NSW coast

Parts of NSW pummelled by a wild storm could be declared natural disaster areas, as 1500 homes were still without power on Monday night.

Conditions have eased on the south coast, but the wet and windy weather has left a path of destruction as it moves north.

All but 1500 customers in the Bermagui area in the state's south had their power restored by Monday evening, after a total of 9000 homes were cut off in the Bermagui, Tilba and Wyndham areas.

"There may still be some people without supply tomorrow morning, for which we apologise," Country Energy's regional general manager Phillip Green said in a statement.

He said the "ferocious storm and flooding" had wreaked havoc.

"Across the area there are kilometres of wires still down taken out by trees, branches and other debris that's been hurled at the network by winds in excess of 100 kilometres an hour."

NSW Emergency Services Minister Steve Whan described it as "a pretty wild storm" and said engineers were working in the hardest hit areas to determine the level of damage.

He said a decision would be made within 24 hours on a possible disaster declaration, which would be triggered if damage to public utilities exceeds $240,000.

"At this stage it looks like most of the damage is to private properties rather than public infrastructure," Mr Whan said.

Sydney also copped a battering on Monday morning as the deluge moved north and onto the central coast.

Offshore, five-metre swells and erratic winds have produced rough conditions and waves of up to three metres.

"We definitely recommend people stay out of the water," Surf Life Saving NSW spokeswoman Donna Wishart told AAP.

Not all NSW beaches are patrolled at this time of year, but Ms Wishart said beaches would be closed due to the weather.

The Bureau of Meteorology (BoM) updated its severe weather warning on Monday evening for coastal areas.

"It should be noted that surf conditions will remain hazardous for coastal activities, such as swimming, surfing and rock fishing along the Illawarra, Sydney metropolitan and Hunter coasts until early Tuesday morning," the bureau warned.

Heavy seas are believed to have claimed the life of a south coast rock fisherman on Friday night, while another angler, aged in his 60s, is lucky to be alive after he was found clinging to the power cord of a boat on Saturday after being washed off Bermagui wharf.

The storm that smacked the south coast on Sunday dumped between 50mm to 140mm of rain in the 24 hours to Monday at 9am (AEST) over coastal areas from Wollongong to the Victorian border.

More rain fell throughout Monday in Sydney and on the central coast and mid-north coast.

Opposition frontbencher Andrew Constance, whose electorate of Bega is one of the worst affected areas, called on the state government to declare the area a natural disaster zone.

"There is no doubt that a natural disaster declaration needs to happen," he said.

"We need to ensure that there is funding available to the community now, particularly our primary industries."