A dead body has been found on the Greek island of Symi where British television presenter Michael Mosley went missing this week, police said Sunday.

"People on a boat saw a body close to the rocky coast," said Petros Vassilakis, police chief for the southern Aegean region.

"The police are going (to the site) to check that it is him," he added.

Greece's ERT public television channel reported that the body was the 67-year-old Mosley.

The authorities had on Friday announced they were stepping up the search after the Briton was last seen alive on Wednesday.

His wife Clare Bailey alerted police when he failed to return from a coastal walk on the island where they were vacationing.

Mayor Lefteris Papakalodoukas said Symi has been baking under "insufferable heat" and the area where Mosley was last sighted was "difficult because it's very rocky".

Much of Greece has seen record temperatures for the first week of June, reaching 39.3 degrees Celsius (103 degrees Fahrenheit) on Symi, which is close to Rhodes.

Mosley is a health journalist well known for appearing on BBC programmes including "The One Show" and "This Morning", and directing documentaries.