Valentino Rossi's row with Marc Marquez has "poisoned" MotoGP, according to Federation of International Motorcycling (FIM) president Vito Ippolito.

The riders collided during Sunday's Malaysian MotoGP in an incident which will see championship leader Rossi start from the back of the grid in the season finale in Valencia.

Yamaha's Rossi and Honda's Marquez have been involved in a war of words during 2015 and Ippolito is unhappy with recent events.

"The recent events arising in connection with the competition for the 2015 FIM MotoGP world title have had a damaging effect on the staging of our competitions and poisoned the atmosphere around the sport," he wrote in an open letter.

"We are moving away from the tradition of pride in sportsmanship that is part of the heritage of motorcycling.

"Everyone has the right to express his or her own ideas. But words and actions always have consequences. Every individual has to take responsibility for those consequences."

Rossi had accused Marquez of trying to help his Spanish countryman Jorge Lorenzo, who is seven points behind in the championship, win the title.

Ippolito is eager to see the feud ended before the final race of the season on November 8.

"Riders, teams, manufacturers and sponsors should not only respect the rules but they should accept the decisions of the officials, whatever they may be," he wrote.

"Otherwise, they are contributing to anarchy and undermining the future development of our sport.

"On behalf of the FIM and all those who are doing their best to bring about a happy conclusion to this Championship, I express the hope that at the next and final round in Valencia the riders will fight it out on the track and in a way that fully respects the spirit of fair play."