A combination of rain and tropical weather meant river levels and the sea surf were dangerously high. Anyone enjoying activities on the waterways was urged to take every precaution and make sure they were wearing life jackets, police said.
Three drownings made the Christmas holiday period - which began at 4pm on Christmas Eve and finished at 6am on Thursday - the lowest toll in six years.
There was an average of 10 drownings during the past five Christmas periods.