Warm and sunny conditions forecast for the Olympic mountain bike races could add another level of peril to an already-challenging course carved out of the dust of a former sandstone quarry.

Riders have been busy prepping the 4.4km layout on Elancourt Hill, a public park which at 231 meters above sea level is the highest point in the Ile-de-France region.

Their verdict is that it will be fast and slippery.

"It's not a typical course which we know from the World Cups, because there's very little forest. But it's very fast, it's going to be extremely slippery," Austria's Mona Mitterwallner, who will take part in the women's race on Sunday, told reporters after her training session.

The course features some tough climbing with a 110m gain per lap while the descents will be white-knuckle rides. It also boasts sections such as The Wall, The Giant Stairs, the Giant Mikado and, appropriately, The Gold Rush.

Rain in the Paris region on Friday could add another dynamic to the layout designed by renowned mountain bike course builder Nick Floros, who also created the track in Tokyo, although Mitterwallner said wet weather could even help take the sting out a course featuring gravelly corners.

"It's one of the only courses where it's more slippery when it's dry, because of the gravel," added Mitterwallner, who just missed a medal at last year's world championships.

"You just have to make sure to be focused from start to finish. Switch off for one second, you will crash."

France's five-time world champion Pauline Ferrand-Prevot will be one of the main favorites for gold in Sunday's women's race which will take around one and a half hours to complete with the actual number of laps determined by teams the day before. Her compatriot Loana Lecomte will also be a contender after winning the test event on the Elancourt Hill.

"It's in her home country, she's the top favorite, so that will put the pressure on, but it can also give her wings," Dutch rival Puck Pieterse said of Ferrand-Prevot.

"We'll find out on Sunday."

Britain's reigning champion Tom Pidcock will be the favorite for Monday's men's race although vastly-experienced Swiss Nino Schurter, winner at the 2016 Games in Rio and runner-up in London, will once again be in the frame.

"It's slippery, it's quite loose and quite wide. If you go fast, it's super slippery. I hope the gravel still goes a bit to the side and makes it less loose everywhere," he said.

"I'm feeling really good. I've had good preparation coming into the Games and I'm feeling super strong."

Pidcock, who abandoned the Tour de France after testing positive for COVID-19, is not a fan of the course though, describing it as bland.

"When you just gravel over a nice hillside, it's not really mountain bike," he said.