Radical changes to how cities will bid to host Olympic Games, and rules allowing more sports to feature, were ushered in on Monday as International Olympic Committee members took bold steps to revamp their movement.

Sweeping alterations to the bidding process were unanimously approved, making it easier and cheaper for host city hopefuls.

IOC members also scrapped a cap on 28 sports for a Summer Olympics, agreeing instead to limit the Games to 10,500 athletes and 310 events.

The move is not good news for all athletes, though. Sports such as baseball, softball, squash or karate can only be added if room is made by another sport which enjoys multiple events.

The votes kick-started a Monaco meeting of more than 100 IOC members which promises to drive change and innovation among the kingpins of global sport.

IOC president Thomas Bach passed his first test with flying colours, all his moves to revamp the Olympic movement receiving overwhelming support.

The changes to the bidding process include allowing hosts to stage some Olympic events in other cities, and even countries.

"The compactness of the Games has to be weighed up against the benefit of using existing venues," Australian John Coates told his fellow members at Monaco's Grimaldi Forum.

"These changes do contemplate different cities and countries hosting the Games, and this is for reasons of sustainability," added Coates, who led a working group looking at the bid process.

Eager to avoid a repeat of the 2022 Winter Games campaign in which four of six candidates dropped out in mid-race over financial concerns, denting the Games' reputation as a lucrative project, the IOC voted unanimously to adopt the recommendations.

The changes are aimed at reducing the cost of bidding and allow candidates to integrate the Olympics into their city plans rather than the other way round.

Changes also include an invitation phase where potential candidates can first discuss plans with the IOC before deciding whether to launch a campaign to stage the Games.

This will avoid a situation like the 2022 bidding debacle.

Cities have spent close to $100 million on campaigns aimed at wooing IOC members to give them the honour of staging the Summer Olympics.