Monday saw residents in Nowra and Terara on high alert as the Shoalhaven River burst its banks with a peak not seen since 1991.

Meteorologists predict the rain to ease in coming days, though expect more showers this coming weekend - but not nearly as heavy as days gone by.

Read more: SES respond to 700 calls on South Coast as evacuated residents return

Alex Majchrowski from the Bureau of Meteorology said rainfall totals from Friday to Monday were "quite heavy" compared to the monthly mean for the month.

"Nowra for August we generally ... [expect] 76mm of rain," he told the Mercury on Monday afternoon.

"So far in the last four days, Nowra has recorded 373mm of rain, and that's not including the fortnight before, or the fortnight before that."

The statistics were not much different for the Illawarra. Kiama recorded around 106mm of rain from Friday to Monday, compared to the monthly average of 80mm; while Albion Park recorded about 230mm compared to the mean monthly rainfall of 53mm.

Although it is unusual for such heavy downpours in the region, Mr Majchrowski said weather can vary quite a lot. So while we haven't seen the Shoalhaven River peak at 4.13 metres for 29 years, elsewhere along the NSW coast may have experienced severe flooding during that time.

"This time of year we are expecting those low pressure troughs and low pressure systems to develop ... [but] generally they can occur anywhere along the NSW coastline," he said.

A trough of low pressure rounded out over the Illawarra and Shoalhaven brought heavy rain, gale force winds and hazardous surf before moving north on Monday.

Between 7pm Friday and 7am Monday, SES volunteers attended to 765 calls for help between Nowra and Moruya. The Kiama SES unit attended to 67 jobs, and Wollongong 95.

The majority of jobs were due to the wild weather bringing down trees, damaging roofs and flash flooding.

Flood rescues and requests for sandbags were also called for.

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