TOKYO: Twenty men will begin their attempt to summit a new peak of competitive climbing on Tuesday when the fast-growing sport takes in a major step into the mainstream with its Olympics debut in Tokyo.

Eight contenders with the best combined score across three events - speed, a vertical sprint; bouldering, which tests problem-solving skills on low walls; and lead, a technical climb against the clock - will proceed to the final on Thursday.

The event will pit the Czech Republic's Adam Ondra, an accomplished technical and outdoor climber, against the dynamic and mold-breaking Tomoa Narasaki from Japan in the race to secure the first men's Olympic climbing gold.

The unusual combined format - the climbing equivalent of a triathlon - has pushed athletes out of their comfort zone with the ranking system creating plenty of potential for upset.

The three walls stand side-by-side at the temporary Aomi Urban Sports Park venue near the Tokyo waterfront with the event to introduce the sport's competitive iterations and many of its big personalities to a global audience.

Climbing's inclusion in the Olympics along with events such as surfing and skateboarding is an attempt by the International Olympic Committee (IOC) to broaden the appeal of the world's largest sporting event.

It brings to the Games a new breed of athlete, some of whom are adept at both competition and climbing rugged outdoor routes.

The sport has become an alternative to traditional gyms as climbing walls spring up in urban centres offering a full body workout to a younger demographic drawn by its associations with adventure.

While the combined format favours all-rounders in Tokyo, climbing will be split into speed and a combined bouldering and lead event at the Paris Games in 2024.

The women's competition begins on Wednesday.