UPDATED: 6:00 pm

The body of a 31-year-old Hamilton man of Thai descent has been found in Waikato River.

The body was spotted in the river at about 7.50am on Sunday by a member of the public who was out for a walk, police said.

The body was about 200m north of the Hamilton Rowing Club.

The man was wearing black shoes, black trousers and a black short-sleeved shirt.

Police are notifying his next-of-kin.

They're treating the death as unexplained, and are asking anyone who saw suspicious behaviour in the area to come forward.

A post-mortem examination will be carried out on Monday.

The river is busy this weekend with the Bridge to Bridge event for speedboats and ski racers on.