The body of a person, believed to be missing Clutha teenager Blake Sinclair, has been found today.

The 18-year-old went missing while kneeboarding on the Clutha River near Balclutha a week ago.

Police said a body was found about 9.30am today by searchers in willows on an island above the Balclutha bridge, about 14km from where Mr Sinclair was last seen.

Previous searches this week had been difficult due to high river levels, which were reduced today by Contact Energy .

The identity of the body was yet to be confirmed pending a forensic examination, police said.

They said Mr Sinclair's family had been "overwhelmed'' by the search effort and support from the Clydevale community and wider community .

The case will be referred to the Coroner .

In a statement, Mr Sinclair's parents said he ``loved the outdoors and all aspects of spending time in the outdoors with family and friends _ including hunting, fishing, diving, boating and trail-bike riding''.

Mr Sinclair was kneeboarding behind a boat on the Clutha River, near the confluence of the Waitahuna River - about 20km up the river from Balclutha - when he was last seen about 3.30pm last Saturday.

He fell from the kneeboard into the river and immediate efforts by those aboard the boat failed to find him, so police were called.