The man, without a life jacket or buoyancy aid, was reported to police at around 12.20pm yesterday as he needed help.
He was taken to sea at the Waitaki River Mouth and spent about 45 minutes in icy water before being rescued, police said.
“While it is fortunate that emergency services were contacted and responded quickly and successfully in this case, it is a reminder that water safety is critical.
“Police are urging anyone near water, regardless of skill level, to take basic precautions to keep themselves safe in case something goes wrong.
“Tell someone where you are going and when you will return. This could be crucial information for us to locate you.”
Police are reminding people to always bring a life jacket when boating or fishing and have a waterproof bag to put their phone in the jacket.
Swimmers and surfers must stick to their limits and if in doubt about the conditions, do not enter the water.
“Be aware of your surroundings and the hazards they may pose – check the local marine weather forecast before you travel and expect changes in weather and water conditions.
“Our southern rivers can be dangerous, and with winter weather approaching, water temperatures are much lower, meaning you are less likely to survive.”