Conditions are expected to create large and powerful surf conditions which are hazardous for coastal activities such as rock fishing, swimming and surfing.

There is a very cold air mass presently over NSW. Daytime maximum temperatures for Friday are expected to be between 9 and 15 degrees.

A complex low pressure system will extend over the Tasman Sea today, Friday, with a small low centre likely to move northwards offshore from the southern and then central coast.

Winds are expected to turn strong and gusty southwesterly over most eastern districts on Saturday, reaching gale-force in parts of the South Coast.

By tonight the main low centre should lie over the central Tasman Sea and is expected to move only slowly to the east on Saturday as a high moves towards western NSW, resulting in further strong southerlies along the coast Saturday.

The wind is expected to ease significantly by Sunday as the high moves east.

The State Emergency Service advises that people should: move vehicles under cover or away from trees, secure or put away loose items around the house, yard and balcony and keep clear of fallen power lines.

For emergency help in floods and storms, ring your local SES Unit on 132 500.