Sustained rain and strong winds threaten coastal towns

Of those, 190 were made from the state's northern region.

A severe weather warning for heavy rainfall and damaging winds stretches from the state's mid-north coast at Kempsey to the Central Coast.

Isolated falls of up to 120mm over six hours are possible, leading to flood watch warnings across the same region.

"We're already seeing those coastal catchments respond quite quickly to rainfall over the weekend," NSW SES operational media coordinator Emily Barton said.

"With the forecast heavy rainfall over the next few days, we're anticipating renewed rises and many catchments to reach minor to moderate flooding.

"SES has pre-positioned flood rescue teams, high clearance vehicles and aviation assets throughout the high-risk areas, but we're urging the community to stay alert."

BoM senior meteorologist Angus Hines said a band of rain that formed overnight into Monday was shifting north to the central and northern coastal regions.

The worst of the rain is expected on Monday and perhaps Tuesday.

Mr Hines called the extended nature of the wet weather "significant" with rain expected in the same region for some days.

"Even though the daily rainfall totals aren't super alarming, having that much rain three or four days in a row can lead to significant flood impacts, road closures and potential for some inundation of homes or properties or businesses," he said.

Mr Hines said the regions with the highest risk of damaging winds were the central, Hunter and mid-north coasts, along with parts of the central and northern ranges.

Dangerous beach conditions are also possible from Sydney's southern beaches to Seal Rocks.

Gusts of around 100km/h are expected over the Hunter and mid-north coast regions.

Wyee, in the Central Coast region, had the state's highest rain total between Sunday 9am and Monday 6am with 121mm.

Nearby, Dora Creek had 117mm.