Rain and possible thunderstorms in Paris have threatened the cancellation of an Olympic test event ©Getty Images

Heavy rain and potential thunderstorms have put the open water swimming Paris 2024 Olympic Games test event at risk this weekend.

The competition is set to take place from August 5 to 6 and is also serving as the fourth meet of the World Aquatics Open Water Swimming World Cup.

Athletes are due to compete in 10-kilometre races between the Pont Alexandre III and the Pont de l'Alma in the centre of Paris but suspending the event is still a possibility.

"If there is no improvement in the weather, it will be complicated", said a City of Paris official, as reported by Le Parisien.

A downpour could bring wastewater into the Seine which could subsequently put the athletes in danger.

The men's and women's 10km races are set to begin from the Pont Alexandre III and are scheduled to take place on August 5 and 6 ©Getty Images
The men's and women's 10km races are set to begin from the Pont Alexandre III and are scheduled to take place on August 5 and 6 ©Getty Images

A test of the river water is due to be carried out tomorrow by Eau de Paris, the company responsible for the public water supply and wastewater collection in the French capital.

Negative readings in terms of bacteria found in samples could force the company to recommend a suspension or cancellation.

Readings from daily tests in June gave "excellent results" according to Paris Mayor Anne Hidalgo. 

Deputy Mayor Paris Pierre Rabadan recalled that last year's testing yielded 92 per cent satisfactory readings which would be suitable for swimming but states that "if it rains a week of torrents, it will be complicated".

A meeting is due to be held tonight between representatives from the Paris 2024 Organising Committee, the Île-de-France Government, Eau de Paris, and the Mayor's office to authorise Friday morning training sessions in the river.

World Aquatics has posted on social media footage from previous events in anticipation that the World Cup leg will ahead as planned.

Since 2016, France has spent around €1.4 billion (£1.2 billion/$1.5 million) in its attempts to clean up the river Seine.

This has seen upgrades to treatment plants, constructions of sanitation plants and storage basins, and connecting houses and boats to modernised waste removal systems.

Public swimming in the Seine has been a key legacy ambition of Paris' hosting of the Olympic and Paralympic Games.

Authorities had banned swimming in the river in 1923 because of high levels of pollution, a problem stretching back to the 16th century when the bodies of those killed in religious wars between Protestants and Catholics were thrown into the water.

Rabadan has claimed that France's first hosting of the Summer Games in 100 years has fast-tracked the project by at least 10 years in regard to investment.