Heavy rainfall, damaging winds and potential flash floods are forecast for the state’s south prompting warnings for holidaymakers to leave campgrounds or risk being trapped by rising waters.

Significant falls will continue along the NSW South Coast through Friday morning, when up to 80mm of rain could fall in six hours, the Bureau of Meteorology has warned.

A severe weather warning for the NSW South Coast on Friday.

A severe weather warning for the NSW South Coast on Friday.Credit: BOM

It will also be a wet weekend in Sydney, with up to 100mm of rain forecast on Saturday and Sunday, with potential thunderstorms developing around the state.

Parts of the South Coast have already received significant rain, including 107mm at Brogo Dam near Bega between 9am on Thursday and 8am on Friday.

Merimbula Airport received more than 103mm of rain in the same period, while 74mm fell at Green Cape, south of Eden.

The severe weather warning along the NSW South Coast follows flash flooding that washed away vehicles and flooded campgrounds in Victoria.

Volunteer rescuers have been put in position to rapidly respond.

NSW SES chief superintendent Dallas Burnes said crews have been visiting high-risk areas, including popular campgrounds along the South Coast, warning holidaymakers of the danger.

“We are asking people to be particularly cautious if they are camping near creeks, rivers or lakes, as water levels can rise quickly and cut-off road access,” Burnes said.