Trio rescued after boat catches fire off popular Sydney beach

Three people were rescued after a boat caught fire off a popular Sydney beach this afternoon.

A NSW Fire Brigade spokesman told 9news.com.au emergency crews raced to Oak Park, Cronulla, just after 1pm, after a skipper called to report a vessel was alight.

The skipper rescued the three men on board, who were all uninjured.

Marine Rescue NSW volunteers are issuing safety warnings to boaters at regular intervals urging them to remain at least 300 metres from the vessel.

9News has been told NSW Fire & Rescue were called off from the job and were told to let it burn because its 500m offshore and not near other vessels.

Thick plumes of smoke can still be seen across the area.

Fire crews said it will burn until it sinks and a salvage operation is likely to take place in the coming days.

A NSW Police spokesman confirmed the boat has been completely destroyed and remains well alight.

The cause of the fire remains unknown.