Queenslander Will 'Dingo' Comiskey has tied for first place in the world's most gruelling horse race, and raised more than $14,000 for the Royal Flying Doctor Service along the way.

Will finished the 1,000km Mongol Derby on Thursday afternoon Australian time, in a three-way tie with Canadian Heidi Telstad and Marcia Hefker-Miles from New Mexico, USA.

The race is a self-guided trek across the Mongolian steppe country on locally-provided horses, eating and resting with nomadic families along the route.

"The generosity of the local people is absolutely incredible," Mr Comiskey said in an interview with event organisers The Adventurists.

"They were more than happy to have you in there on the floor with the kids, or next to grandmother."

Originally from Dingo in Central Queensland, Mr Comiskey now works on a property at Boggabilla near the New South Wales-Queensland border.

His mother Pip Comiskey said the event was scheduled to take 14 days, but the three winners completed the race in just 10.

"They were happy with the tie," Ms Comiskey said.

The leaders of the race, Marcia Hefker-Miles, Heidi Telstad and Will Comiskey. ( Mongol Derby: Richard Dunwoody )

"They'd done the challenge together, they'd had the experience together, and they thought that was a suitable way to end.

"Obviously they share a very strong bond, those three riders."

The horses provided to riders for the event were changed every 40km, using on a system based on Genghis Khan's postal network.

The event organisers describe them as "semi-wild", and Ms Comiskey said Will's background in horsemanship would have come in handy during the event.

"He's given rodeo a shot and loved that, I think he was out there to join in the fun and do his best.

"The horses looked pretty little — Will isn't excessively tall and his legs were dangling, so they're pretty nuggetty little ponies."

2014 Mongol Derby winner Sam Jones, from the WA Wheatbelt, with this year's winner William Comiskey at the race's finish line. ( Mongol Derby: Richard Dunwoody )

In his interview with The Adventurists, Will said the horses were very tough and well suited to the terrain.

"The country just doesn't even faze them," Will said.

"They can carry themselves a long way, which is incredible.

"They could gallop for 30km, they handle that no worries.

"Then you'd have your slow pony who would rather eat — I picked a couple of those, walked a few miles beside them."

Before the race Will set out to raise $10,000 for Royal Flying Doctor Service.

His fundraising has now passed $14,000 and is still rising on the back of his win.

Willl's father has passed away, and his mother Pip said he would have been in Will's mind during the event.

"I know he was probably doing it with his father on his shoulder," Ms Comiskey said.

"Having lost his father, I think he was thinking about a result that would make his father proud."