Boat skippers should consider delaying or changing voyages on Wednesday after the Bureau of Meteorology warned of dangerous surf conditions expected to hit the NSW coast this week.
Rock fishers should avoid coastal rock platforms exposed to the ocean and seek a safe location sheltered from the surf.
Surf conditions are expected to be hazardous for boating, swimming and rock fishing throughout the day on Wednesday, the BOM has advised.
Roads and Maritime Services has issued an alert and advised skippers to check forecasts, ensure their equipment is suitable for observed condition and wear a life jacket.
Rough conditions struck the NSW coast earlier in the year, when 150 people were rescued in one weekend in February.
Surf Life Saving NSW rescued 15 people in a single incident after the group ran into trouble in dangerous waves at Broulee on the state's south coast on Sunday.
Read more: Dangerous surf batters the Hunter