The Bureau of Meteorology forecast a deep low pressure system off the central NSW coast will continue to push winds up to 90km/h to parts of the Illawarra, Snowy Mountains, Southern Tablelands, ACT and South Coast.

For Alpine areas above 1900 metres, winds may average 80 to 90km/h with peak gusts in excess of 120km/h.

Read more: Illawarra road closure, power cuts after heavy rains and strong winds

Winds are expected to ease throughout the morning as the low weakens and moves east.

The bureau forecast very heavy surf may lead to localised damage and coastal erosion, with large waves likely south of Wollongong. People are advised to stay away from these areas.

Meanwhile, the South Coast has been pummelled by wild weather which has led to flooding and landslides.

Residents of Sussex Inlet were told to evacuate on Monday night after heavy rainfall led to flooding in the area. The Bureau of Meteorology expected the inlet would rise to 1.2m by 9am Tuesday but had hit 1.24m by 1am.

The State Emergency Service said the moderate flooding would impact low-lying areas including caravan parks and homes.

Wild weather led to widespread power outages on Monday night, which forced the SES St George's Basin unit to seek shelter. A landslide at Pooh Corner on the Kings Highway affected traffic for several hours.

On Monday, the unit had responded to more than 200 callouts to assist with leaking roofs, fallen trees, flooding and sandbags.

"We take this opportunity to remind our community to avoid driving in this weather and definitely not through any floodwaters, no matter how familiar the road/area is to you. Please also avoid parking under trees wherever possible," a post to its Facebook page said.

The SES Kiama unit performed several rescues throughout the day, including several motorists stuck in floodwaters and a herd of six cows.

A Flood Warning is current for the Deua River and St Georges Basin on the South Coast. A Flood Watch is also current for the South Coast river catchments.

Locations which may be affected include Wollongong, Batemans Bay, Eden, Moruya Heads, Cooma, Bombala, Bredbo, Adaminaby and Nimmitabel.

In the Batemans Bay and Narooma areas 1,874 people are still without power on Tuesday.

An Essential Energy spokeswoman said trees had fallen onto powerlines in several locations and caused "significant damage" to the network.

"Crews worked throughout the night in challenging conditions to restore power to approximately 4,800 homes and business across the region," she said.

In the ACT, around 80 people are without power in Canberra's north, according to Evo Energy.

Read more: Thousands of homes, businesses without power as wild weather lashes coast