A powerful low-pressure system is hammering the coast at the moment and conditions won't ease until tomorrow (Friday August 23).
The system is expected to create 'Hawaiian-style' conditions consisting of big surf, with waves up to 12 feet high and strong winds.
Surf Life Saving NSW advises that people heading to the coast should be aware of the dangers associated with the anticipated system including powerful waves in surf zones and against rock platforms, fast movement of water and currents, long periods between wave sets and erosion of beaches.
The forecast extra-large swell means most of the NSW coast will be extremely hazardous for all activities especially boating, surfing and rock fishing.
SLSC lifesaver and surfer Nick Carroll says even experienced surfers need to be wary.
"The risk for unaware surfers is that the swell will rise quickly," says Carroll. "It could be four-feet and manageable on Thursday morning, but when the big pulse begins to arrive it will happen very quickly and could catch people out."
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Although the Surf Lifesaving season does not begin until September 28 volunteer surf lifesaving support operation teams are on-call 24-7 to respond to critical incidents.
"We have some of the most experienced coastal emergency responders in our call-out teams," said SLSNSW CEO Steven Pearce.
"However, we strongly advise people to consider the potential danger they are putting themselves and our volunteers in before venturing into the water during this swell event.
"If you do intend on swimming please make sure you only swim at one of the 12 locations patrolled during winter and always swim between the red and yellow flags.
"If you do see someone in danger please call triple zero (000) immediately. Do not attempt a rescue on your own."
There were 44 coastal drowning deaths in NSW between 1 July 2018 - 29 June 2019. Rock fishing resulted in eight deaths.
Hazardous Surf Conditions Safety Tips
Avoid rock fishing and water activities on exposed beaches/rock-shelves
Only swim at patrolled beaches, between the red & yellow flags. See the websitewww.beachsafe.org.au for patrolled locations/times
Check the official Bureau of Meteorology (BOM) forecast before undertaking rock fishing and water activities
Boaties should seek advice from Marine Rescue NSW and always wear a lifejacket
If witnessing an in-water emergency dial 000 - Police