Dunedin City Council aquatics manager Nicola Jukes said the large amounts of sea water washing into the pool over the past two days was cooling the heated pool and filling it with seaweed and sand.
The pool is due to reopen for the summer on Monday and staff are concerned it may not be possible to reheat the water to its usual balmy 28degC by then.
``It will depend on what happens over the next couple of days.
``It may be that we open and the pool might be a bit cooler. It was up to a good temperature, but with all this cold weather coming over, it's cooled it off again.
Staff were busy vacuuming the sand off the bottom of the pool and removing seaweed while the water was pumped through a heating unit.
It took up to four days to bring the water temperature back up to 28degC, she said.
Either way, she said it would still be warmer than swimming in the sea on Monday.
The pool has been closed over the cooler winter months, and keen outdoor swimmers are expected to return in flocks.
The pool will remain open from 6am to 7pm on week days and 7am to 7pm on weekends until March 31 next year.