Italian orienteering athlete Mattia Debertolis died after being found unresponsive during competition at the World Games in Chengdu, organisers said.

The 29-year-old was discovered unconscious during an orienteering event on August 8 and died four days later, said a joint statement from World Games organisers and the International Orienteering Federation (IOF).

The World Games is a multi-sport event held every four years for disciplines not included in the Olympics.

"Despite receiving immediate expert medical care at one of China's leading medical institutions, he passed away," the statement said.

It did not provide details on the cause of death.

Debertolis, from Primiero in eastern Italy, was taking part in the final of the men's middle-distance, the first medal event of the Games.

Footage from the World Games' social media accounts showed athletes running through crop fields and villages on a largely rural course.

The winner, Switzerland's Riccardo Rancan, completed the course in 45 minutes and 22 seconds.

Debertolis was listed as "Did Not Finish" in official results, along with 11 other athletes. (AFP)