Swiss rider Gino Mäder died on Friday from the injuries he sustained when he plunged into a ravine during the Tour de Suisse.

The 26-year-old Bahrain Victorious rider fell during a high-speed descent on the fifth stage between Fiesch and La Punt on Thursday, after an exhausting day marked by three ascents over 2,000 metres altitude.

He had been found "lifeless in the water" of a ravine below the road, "immediately resuscitated then transported to the hospital in Chur by air", organisers said.

But the next day, "Gino lost his battle to recover from the serious injuries he sustained", Bahrain-Victorious said in a statement.

"Despite the best efforts of the phenomenal staff at Chur hospital, Gino couldn't make it through this, his final and biggest challenge, and at 11:30am we said goodbye to one of the shining lights of our team," the team added.

"Our entire team is devastated by this tragic accident, and our thoughts and prayers are with Gino's family and loved ones during this incredibly difficult time."

As a result of his death Friday's stage has been declared void although the riders will still ride the route as a tribute.

Mäder had enjoyed a strong start to the season, finishing fifth in the Paris-Nice race.

"As riders, we should also think about the risks we take going down a mountain."

Tributes poured in from the cycling fraternity.

Two-time Tour de France champion Tadej Pogacar led them, posting on Instagram: "Rest in peace (heart icon) I will miss you," with his fellow Slovenian and recently-crowned Giro d'Italia winner Primoz Roglic tweeting: "Speechless."

Former Tour de France winner Geraint Thomas, who finished runner-up to Roglic in the Giro, tweeted: "I can't believe what I'm reading. Such a sad sad day. Thoughts with everyone who knew and loved Gino."

The Giro also took to Twitter to pay their respects: "Cycling is a big family. Today we all cry for a special boy. Your smile will forever be in our hearts. Ciao Gino."

American rider Magnus Sheffield also fell on the same descent from Albula, during the most difficult stage of the race with multiple climbs. The Ineos-Grenadiers rider was hospitalised with "bruises and concussion," organisers said.

On Thursday, world champion Remco Evenepoel criticised the decision to compete on such a dangerous road.

"While a summit finish would have been perfectly possible, it wasn't a good decision to let us finish down this dangerous descent," the Belgian wrote on Twitter.