Cyclists are racing at speeds of more than 60 kilometres an hour on Melbourne's shared walking and riding trails, putting other trail users at risk of injury for the sake of bragging rights on a popular app.

The informal time trial competition, among a small subculture of reckless riders using an app called Strava, has been condemned by cycling and walking advocates as a threat to public safety and enjoyment of the outdoors.

The cycling app contains a multitude of digital time trial tracks around Melbourne created by users – from busy paths in built-up areas such as Docklands to winding creek trails in Doncaster – in which riders have clocked themselves at speeds of between 45 km/h and 65 km/h.

Leading cycling organisation Bicycle Network is so concerned it has appealed to San Francisco-based Strava to prevent the app being used for time trials on shared trails, in the hope this will remove the incentive to race.

Spokesman Chris Carpenter said riding at top speed on shared trails was "completely inappropriate".