The body of a missing 23-year-old British tourist has been found in a Venice canal near where he had been staying with his fiancee for Saint Valentine's day.

"We have discovered the body of a British tourist, Richard John Raynor, in a canal under a bridge," police officer Alessandro Guiliano told AFP Sunday.

While there were no indications Rayor's death had been violent, "we are not ruling out any hypothesis," he said.

A native of Doncaster, Rayor disappeared overnight Wednesday, only hours after arriving with his girlfriend Katie Robinson, 22, for a three-day break in a hotel in Mestre, outside Venice.

According to Il Corriere della Sera daily, the girlfriend told police they had an argument after spending the evening in bars in Venice and she returned to the hotel alone by taxi, leaving Raynor in town.

Since then, she said, Raynor had left no word apart from a message on her mobile phone the next day saying he was lost.

His wallet, hotel room keys and mobile phone were found opposite their hotel and handed in by passers-by. The young woman then alerted the police, who opened an inquiry.

Rayor's father arrived Saturday in Mestre, where he was questioned by police.