The Bureau of Meteorology is predicting an east coast low could hit the South Coast early next week.
The weather system could potentially bring heavy rain, gale force winds and a risk of flash flooding on Monday July 13 and Tuesday July 14.
BOM Meteorologist Helen Kirkup said by Sunday the Bureau will have a clearer picture on the severity of the storm.
"It's still unclear exactly where and how big it will be and how it will move," she said.
"At this stage it looks like on Monday and Tuesday, the Illawarra and South Coast are likely to see the impacts from this system.
"It will be a low off the coast but at this stage whether it will become an east coast low is a bit 50/50."
South-easterly winds accompanied by rainfall between 50-100mm is expected at this stage but if the weather system really hits the South Coast, rainfall could reach upwards of 150mm.
If there are any concerns of flooding, BOM will likely put out warnings on Saturday.
The St Georges Basin SES Unit has already urged residents to start preparing their home ahead of the forecast low.
St Georges Basin SES will be open this Saturday and Sunday for sandbag filling and collection. For residents of Sussex Inlet, Cudmirrah and Berrara, they will be delivering sand and bags to those areas.