SURF Life Saving NSW is warning swimmers about dangerous surf conditions which stretch from the Victorian border to Yamba in Northern NSW for May 4.

A Southerly swell is expected to reach 3 to 4 metres at its peak late in the afternoon, with a swell period around 12-13 seconds.

These conditions will be hazardous for coastal activities such as swimming, surfing and rock fishing.

Conditions are expected to ease on Monday.

“With the onset of these dangerous conditions we strongly encourage swimmers to follow all safety warnings and avoid entering the water unless there is an active patrol on duty, which will be signified by the red and yellow flags,” Surf Life Saving NSW lifesaving manager Andy Kent said. 

“While the official patrol season has ended there are still some locally patrolled beaches in metro areas and I would not encourage anybody to swim in an un-patrolled area during this time frame.”

At the beach, follow these simple safety tips:

* Always swim between the red and yellow flags

* Read the safety signs

* Ask a lifesaver or lifeguard for safety advice

* Learn how to identify a rip

* If you need help, stay calm and attract attention

* Always wear a lifejacket while rock fishing

* If witnessing an in-water emergency call 000 Police

* For full details on which beaches are patrolled and patrol times during winter go to beachsafe.org.au, which is also available as an iPhone app.