The search for a man missing in Lake Alexandrina has finished for today and will recommence on Monday.

The alarm was raised about 11.30am on Friday 27 November, after two men set off on an inflatable canoe from Sheoak Road just north of Milang and failed to return.

Water Operations Unit officers coordinated a search and rescue effort which included local police, Sea Rescue Squadron boats and PolAir.

About 2.45pm miraculously one of the men, a 19-year-old from Elizabeth Vale, was found floating in the water and was treated by SA Ambulance crews for hypothermia.

The canoe was also located.

The search for the second man, a 31-year-old Brahma Lodge man is continuing, however police hold grave concerns for his welfare.

The search concluded this afternoon and will recommence on Monday.