Emergency services were called to the area shortly after 2pm following reports two men were being swept out to sea, Senior Sergeant Craig Brown said.
The men were in a party of five who walked to Moturata (Taieri Island) during low tide earlier that day to gather mussels.
The group had underestimated high tide, with two of the party getting "into trouble, and getting swept away to the north", he said.
Fortunately, the pair - a 17-year-old and a 25-year-old - were assisted back to shore by some nearby whitebaiters, Snr Sgt Brown said.
The men were attended by St John staff at the scene, with one transported by ambulance to Dunedin Hospital as a precaution.
Police attended a "reasonable number" of callouts to Taieri Mouth each year, and "this could have been far worse if no-one was there ... [There was a] high likelihood of a fatality."
Those wanting to enjoy the area should take note of tide and weather conditions, Snr Sgt Brown said.
On Saturday afternoon, three Dunedin men were rescued by the Brighton Surf Life Saving club after becoming stranded.
