The SA Weather Service (Saws) has warned residents and visitors to the coast to be cautious ahead of expected spring tides bringing rough seas this week.

The highest tides - stretching from the Cape through to Richards Bay in KwaZulu-Natal - will be experienced on Thursday and Friday, just ahead of the December 16 long weekend.

"Care should be taken on the days leading up to and following these periods as high tides will be higher than average and low tides will be lower than average.

"Caution is advised for areas which may be exposed to the lower-than-normal low tide but will flood when the tide rises.

"Furthermore, certain areas that are normally accessible may be flooded due to the higher-than-average high tide, like rocky outcrops and headlands."

Saws also appealed to beachgoers to be mindful of rip currents.

"It is recommended that beachgoers swim only at beaches with lifeguards, and only within demarcated swimming areas."