Large waves will pummel the NSW coast during the next two days as an intense low pressure system spins over the Tasman Sea.

Blustery southerly winds and showers on the western side of the low pressure system are making the start of winter feel appropriately chilly along the NSW coast today. Wind gusts have been hovering around 80-90km/h at Wattamolla this morning, after reaching up to 100km/h overnight.

In addition to the cold and windy weather, even stronger winds over the Tasman Sea have whipped up large waves during the last 24 hours.

A waverider buoy located about 5-10 kilometres off the coast of Sydney's Northern Beaches registered a maximum wave height of 9.2 metres early on Friday morning. Further south, a height of 9.36m was registered off the Illawara Coast, near Port Kembla.

The large swell has prompted a severe weather warning for damaging surf and abnormally high tides, which may cause coastal erosion and seawater flooding in low lying areas. The combined effect of the wind and waves pushing water up against the shoreline may cause the water level to exceed the highest tide of the year by around half a metre tonight in some areas. 

For experienced surfers wishing to brave the large waves, the combination of a southerly swell and brisk southerly winds will make south facing beaches rough and messy. The cleanest waves will be found at more protected spots, such as beaches and rock shelves facing to the east and north.

The wind and waves will ease gradually from Saturday as the low pressure system moves away from the NSW coast and heads towards New Zealand's North Island.