A lost kayaker who spent the night on a sandbank in waters north of Adelaide says he is “happy to be alive and well” after being rescued on Wednesday.

Goran Radic was found near Middle Beach during an extensive water and aerial search overnight and again this morning after relatives raised the alarm just before 11pm on Tuesday.

The 73-year-old said he had been paddling his one-person kayak in waters 40 kilometres north of Adelaide, a trip he has made “about a thousand times”, when he became disoriented on Tuesday.

Missing kayaker Goran Radic is wearing sunglasses and smiling

Goran Radic says he “didn’t panic” while he was missing in waters off Adelaide overnight. (ABC News)

“The moment I didn’t see entrance into the channels I knew something is [sic] different,” he said.

He said he was wearing a life jacket but left his phone in his car.

“I didn’t panic. I was alright,” he said.

“I’ve seen rescue helicopter sometime in the night and they missed me.”

A red and white helicopter with an open side door lands on a sandy area

A rescue helicopter brought Goran Radic back to shore. (ABC News)

He said he tried to paddle to St Kilda, about 20 km south of Middle Beach.

“I thought lights going to guide me to St Kilda but didn’t find it so I kayaked back. They found me this morning,” the Aldinga Beach resident said.

SA Ambulance Service Special Operations’s Clinton Daniels said they rescued the man by landing a helicopter on a sandbank.

A paramedic in lifejacket with a rescue helicopter in the background

Clinton Daniels was one of the rescuers. (ABC News)

“We were able to land on a bank and actually get him to walk across to the aircraft and [he] climbed in,” Mr Daniels said.

“He had appropriate clothing and stayed up all night waiting for daylight and possibly help.

“He’s had a fairly decent ordeal, but he’s doing quite well.”

A man smiles and waves goodbye next to his car with the door opened

A grateful Goran Radic waves goodbye to his rescuers before driving home. (ABC News)

Once Mr Radic got to safety, he rang his wife before driving home.

“She’s happy I’m alive, alright, and [asked me] what happened,” he said.Extensive search efforts

SA Police’s Water Operations Unit, Polair with infrared camera capabilities and Volunteer Marine Rescue were part of the overnight search.

two men in dark uniforms stand next to a police dinghy

The SA Sea Rescue Squadron hovercraft helped in the search. (ABC News: Briana Fiore)

Paramedics assessed the kayaker when he landed and deemed him to be in good health.

Kevin Dixon, a volunteer rescuer who took part in the search from 1am, said the man was “very lucky” to be alive.

Mr Dixon said the mangroves were full of mosquitoes and sea life but that conditions early today were flat and calm.

He said it was not a cold night, which was in favour of the kayaker.

Mr Dixon said the search was stopped at 3:30am and resumed at first light.

Two officers in helmet on a hovercraft, one of them holds a kayak attached to the side, on wetlands

Kevin Dixon and Steve Everett retrieved the man’s kayak. (ABC News: Briana Fiore)

He said he initially feared the search would be a recovery effort but was happy with the good news.

“Watch the weather and always wear life jackets, doesn’t matter what the day is,” Mr Dixon said.

“Tell everybody where you’re going and keep your radio handy.”

Mr Dixon and another rescuer, Steve Everett, found Mr Radic’s kayak just after midday and pulled it to shore with the guidance of police in the air.

The kayaker said he was grateful for his rescuers.

“Thank you so much. They’re professionals,” he said.

Mr Radic says he plans to head out on his kayak again but will “be more careful”.