Missing SA swimmer feared drowned

A 26-year-old Adelaide man missing in waters off South Australia's Yorke Peninsula is now presumed drowned.

The search for Dylan Zidarich was suspended on Tuesday afternoon but was scheduled to resume at first light on Wednesday.

Police were called to the area on Monday after reports Mr Zidarich had got into trouble while swimming at Ethel Wreck Beach near Marion Bay.

"Witnesses lost sight of the man and it's believed he may have been swept towards the cliff area, making retrieval by water extremely dangerous," police said.

They said the search would now focus on recovering the missing man's body with drones to be brought in and a ground search to be conducted along the Yorke Peninsula coast.