Former Geelong champion Paul Couch, the 1989 Brownlow Medallist, has died from a heart attack.

Couch, 51, was riding his bike with friends along the Great Ocean Rd, near Apollo Bay, when he fell from his bike. It's understood he went into cardiac arrest and could not be revived.

In a statement, Victoria Police said: "Police and other emergency services were called to the Great Ocean Road in Marengo this morning following reports a man had died after coming off his bike about 8.40am.

"The 51-year-old Grovedale man was riding with people known to him and at this early stage, his death is being attributed to some sort of medical condition.