Police said they recovered the man's body after members of the public spotted it in the river near Teviot and alerted police about 4.30pm.
"While a post mortem and formal identification process is yet to be completed, it is believed to be that of missing man Rian Williamson."
Williamson’s family has been advised and further updates will be provided when available, police said.
On Friday, Central Otago police asked the public to help find Williamson after he was last seen in Roxburgh at about 10.30pm on Wednesday.