Heat levels during the Paris Olympics could pose health risks for competitors, a report by environmental groups said, adding that continued increases in global temperatures could jeopardise future editions of the Games.

The report, titled "Rings of Fire: Heat Risks at the 2024 Paris Olympics", was published on Tuesday by the British Association for Sustainable Sport and Frontrunners, an organisation helping athletes engage in environmental issues.

Temperatures are expected to soar again in the European summer, after setting records in 2023, with French national weather agency Meteo-France saying that conditions are likely to be warmer than normal.

Heat and humidity was also a major issue at the Tokyo Olympics, where athletes - even those well-used to training in hot climates - found it extremely tough going.

"The next Olympics in Paris is now upon us, and notable cases of extreme heat undermining the health and enjoyment of sporting spectacles have only increased in the intervening years (since the Tokyo Olympics)," said the report, whose researchers spoke to both scientists and athletes.

"The fact that the Olympics will take place during high summer means that the threat of a devastating hot spell is a very real one," it said.

The report, which looked at data from the past 100 years since the Games were hosted in France in 1924, found that temperatures had increased by 3.1 degrees celsius on average during the months of July and August - when the Olympics are traditionally held.

British men's rugby sevens player Jamie Farndale warned of the dangers athletes could face due to the heat, adding: "What we do is push ourselves to our limits, and if we have to do so in conditions that are unsafe I don't think the athlete would hold back."

The International Olympic Committee (IOC) told Reuters that among several countermeasures identified, one involved reviewing the competition schedule, which has been planned to avoid potential excessive heat.

"It is of great importance that organisers of summer sports events plan carefully to prevent heat-related illnesses," an IOC spokesperson said.

"For the Olympic Games, providing athletes and spectators with the best and safest conditions possible are top priorities for the IOC and the entire Olympic Movement."