An Australian man has died during a motorcross rally in Borneo during which riders were forced to spend the night in the jungle when heavy rain flooded the track.
An organiser of the 140-kilometre race said Michael Adrian Headley, 34, suffered a heart attack and died on Saturday, midway through the Balikpapan Two Days Enduro race.
"He had a heart attack and died instantly. He seemed to have forced himself beyond his physical ability," race organiser Harin Tasmida said.
Mr Headley lived with his family, including his young son, in the coastal city of Balikpapan, where he worked for a mining company.
Mr Headley's wife posted a message on her Facebook page farewelling her husband, a former Queensland resident.
"daer my lovely husband,happy b'day darling...I'alwasy love you so much," she wrote.
"happy b'day dady..maeson miss dady so much..bye bye dady..maeson alwasy love dady very so much."
A Department of Foreign Affairs and Trade spokesperson confirmed the Australian man's death.
"The Department is providing consular assistance to the family, in Australia and in Indonesia, of a 34-year-old Australian man who died on 16 February in Kalimantan," the spokesperson said.
Twenty other riders had to be rescued during the race after they were forced to spend the night in the jungle when heavy rain made the track impassable.
"Many motorcycles broke down on the trail and riders had no choice but to stay overnight in the jungle without food and water, many suffering from fatigue," local rescuer Trembli Vemberiyanto said.
Tasmida, however, denied the event was poorly organised, saying they responded as quickly as possible.
"Nobody went missing. They only got stuck in the jungle because of the muddy terrain as it was raining a night before. We sent them food and water," he said.
The Balikpapan Two Days Enduro began on Saturday with around 800 participants in the city of Balikpapan. The event was part of the city's 116th anniversary celebrations.
The organiser said Headley had undergone a physical examination in Singapore two months earlier and had been in good condition.