Mehdi Habibi was swept from rocks by a large wave on September 1, and has not been seen since. (Supplied by family)

In short:

Mehdi Habibi was posing for photos when he was swept into the water off of Granite Island on September 1. 

The boy has not been found despite an extensive sea, air and land search for 10 days.

SA Police have thanked the volunteers and emergency services for their search efforts.

The search for a missing teenager has concluded days after he was swept off rocks on South Australia’s south coast with no sign of the boy, police say.

Blair Athol teenager Mehdi Habibi was struck by a large wave about 3pm on Sunday, September 1, on Granite Island.

The teenager’s aunt, Fahema Habibi, had previously said her family had arrived in Victor Harbor for a “party and picnic” on Father’s Day.

His family said the boy had ventured onto the rocks with his younger brother, who was filming when Mehdi slipped into the water.

His disappearance has prompted an extensive sea, air and land search for 10 days, with crews forced to contend with challenging weather and ocean conditions.

“Unfortunately, the youth has not been located and the search efforts concluded at last light on Wednesday, 11 September,” SA Police said in a statement.

The search effort spanned 10 days. (ABC South East SA: Caroline Horn)

Ms Habibi previously said the two brothers were on the island, which is connected to the mainland by a 600-metre causeway, when the elder boy was washed into the ocean.

“I think they take pictures and video and then I think maybe he [was] slipping his legs on the rocks,” she said.

SA Police said crews had searched the coastline from Victor Harbor to the Murray Mouth on foot and in vehicles over the past 10 days.

Police said helicopter and specialist divers were deployed, as well as drones to search rock cavities. 

“Police would like to thank the volunteers and emergency services involved for their dedicated efforts throughout the 10-day operation,” the statement said.

Mehdi Habibi’s family said they were continuing to travel to Victor Harbor every day to search for him.