A deepening Tasman Low is driving heavy rain, blustery winds and powerful surf into the NSW coast this morning, with warnings in place for some areas.

The low pressure system has already caused two days of heavy rain and snow in southeastern parts of NSW. A rain gauge at Black Range, near Bega, collected 140mm during the 46 hours to 7am today.

Now, the dangerous weather is spreading further north. Rain and blustery winds have been hammering the NSW coast from the South Coast up to the lower Mid North Coast during the first hours of daylight this morning.

Image: Visible satellite and radar image showing the Tasman Low driving cloud and rain over the NSW coast on Tuesday morning.

This morning's highest wind gusts as of 8am have been 102km/h at Bellambi, 87km/h at Kiama, Wattamolla and Norah Head and 83km/h at Sydney Airport and Kurnell.

Heavy rain has also targeted coastal areas this morning. Sydney's Observatory Hill received 13mm in one hour as a downpour hit the city shortly after 6am. Further south, Point Perpendicular had seen more than 20mm of rain between midnight and 8am.

The powerful winds are also whipping up large and dangerous waves along the NSW coast. A waverider buoy off Batemans Bay registered maximum wave heights of 7.3 metres at 6am. Further north, maximum wave heights were up to 6.4 metres off the coast of Sydney by 7am.

Image: Observed wave heights off the coast of Batemans Bay on Tuesday morning. Source: Manly Hydraulics

Blustery winds, rain and powerful surf will continue to lash the NSW coast throughout Tuesday. At 8am, a severe weather warning was in place for damaging winds and damaging surf between the South Coast and the Mid North Coast, including Sydney.

Wind and rain will ease from Tuesday and the large waves will start to back off later in the week.