Four-time Tour de France champion Chris Froome and Hong Kong's two-time Olympic medallist Sarah Lee were among those who took part in this year's Hong Kong Cyclothon.

The 50-kilometre race kicked off in Tsim Sha Tsui at around 5.15am on Sunday, and the route includes Tsing Ma Bridge, Ting Kau Bridge and Stonecutters Bridge, as well as several tunnels.

Froome said he very much enjoyed his first Cyclothon, as the ride in Hong Kong is very different from racing in Europe.

"Seeing Hong Kong by bike through all the main roads, it's just such a pleasure. I think these are roads that cyclists would never normally get the chance to enjoy," the British rider said.

"So to be able to really take in the city, take in the surroundings, yeah, just such an amazing experience."

Lee, for her part, said while it's her third time taking part in the Cyclothon, this is the first time where she wasn't going for speed and has more time to enjoy the experience.

"I think the most beautiful part of the route is the Stonecutters Bridge. Usually you look at the bridge from the pier, you already find it beautiful -- but when you actually ride a bike on the bridge it's a different feeling," she told reporters.

"In terms of difficulty, it's really the general situation in Hong Kong, you have to make sharp U-turns in many places [along the route]. If there are earlier traffic signs about them, it'd be better."

Organisers said a record 6,000 people joined this year's Cyclothon.

As part of the event, the Tourism Board also hosted a sports carnival at the West Kowloon Cultural District, with local food stalls, yoga sessions and freestyle cycling performances all part of the programme.