Olympics organisers remain “hopeful”  triathlon events will be able to proceed on Wednesday after the men’s competition, originally scheduled for Tuesday morning, was postponed due to water quality in the Seine.

Swimming training for the triathletes was cancelled on Sunday and Monday and the decision has been taken to move the men’s race, which has been rescheduled to take place at 10.45am local time after the women’s race.

Further postponements or cutting the swimming section to turn the competitions into a duathlon remain a possibility.

Paris 2024 Olympic Games – Day Two
A general view of the pontoon, moored on the River Seine, that is used by Triathlon athletes  (David Davies/PA).

Aurelie Merle, executive director of sports competitions at Paris 2024, said: “The priority of the IOC, of Paris 2024, is for the health of the athletes, and the tests that were carried out on the Seine were not sufficient on the entirety of the course.

“That’s why we immediately informed the athletes and the coaches as soon as the decision was taken at four o’clock in the morning.

“You have of course been witnessing that we have had meteorological events which were beyond our control that took place, such as the rainfall over Paris on the 26th and 27th affecting our water quality, which compelled us to reschedule this event.

“The whole world has witnessed that it rained heavily in Paris during the opening ceremony, but also the day after.

“As you know we also had to postpone the skateboarding competition for that reason. The equivalent of July in rainfall fell in just 36 hours, which is like 25 millimetres, which is a lot.

“We are quite hopeful because as you can see the weather conditions have been quite good over the past few days with the return of the sun and quite high temperatures, which will have a positive impact on the water quality combined with all the infrastructure that has been put in place.

“So we are hopeful that we can organise these two competition events tomorrow.”

Merle revealed that of the four samples taken along the Seine one was below the threshold, two were “just slightly above” and one “a bit more.”

She said: “I think it is key to understand that the sample is taken 24 hours before. I mean, actually, we even reduce that time to 21 hours and 30 minutes in line with World Triathlon to ensure that we have the most accurate information.”

Paris 2024 Olympic Games – Opening Ceremony
Paris had heavy rainfall during the opening ceremony last Friday night and the following day (Mike Egerton/PA).

She added: “From the results we can tell we are very close to the threshold. We know that the Seine and the heat have a very strong impact on the quality of the water, and that’s why we feel, because we are so close, this morning, we hopefully believe that the water quality will be better.”

Merle said the samples are part of a larger mechanism of research that also includes data from microbiology tech firm Coliminder and updates from a weather forecast specialist who is also present in the decision-making meetings.

The competitions boss confirmed that the specific concern was the bacteria E.coli, which in its pathogenic form can cause serious illness by disrupting the normal function of the intestines.

French weather service Meteo France has put the Paris region under a weather alert from 6pm local time on Tuesday night, citing a “risk of thunderstorms with heavy rain and locally hail and gusts of wind” leaving many journalists in the International Olympic Committee’s morning briefing wondering why Merle and her team remained so optimistic.

She said: “We had a discussion with Meteo France this morning, and there is a chance that there could be some storms and maybe some rain later in the day, but they will provide us with more accurate information at three o’clock so we know exactly what this means in terms of localisation, because we are talking not only about (whether) it’s raining but where it’s raining.”

Britain’s Alex Yee is one of the favourites for gold in the men’s race while Beth Potter is the reigning women’s world champion.

World Triathlon confirmed on Tuesday morning that Friday remains a contingency day if one or both of the races are unable to go ahead.

Another possibility could be that the competition is instead transformed into a duathlon, confirmed by World Triathlon president Marisol Casado on Friday.

The 67-year-old former triathlete acknowledged stakeholders were “disappointed” by postponement, but insisted “we are all all in a good mood thinking that we are going to have the opportunity.

“We have very clear cooperation from the coaches in order to reorganise, and the feeling of the athletes, we know they take it that it is not the first time that it happened to them.”

Both the men’s and women’s competitions were changed to duathlons due to the quality of the water in Madrid at the 2023 Europe Triathlon Championships last June.

Cadado defended accusations that the Seine was selected with aesthetic rather than athletes in mind, pointing to the fact that there is athlete representation on her executive board and that “they are a part of our chosen situation here”.

Marathon open water swimming events, taking place on August 8 and 9, are also scheduled for the Seine, but reports have suggested a backup venue at canoeing and rowing venue Vaires-sur-Marne is a possibility.

Asked why no such option was considered for triathlon, Merle said the difference came down to the fact that, while working “very closely” with Cacados organisation on contingency plans, the difference was that triathlon had the “last-resort” duathlon “opportunity”, while marathon swimming simply could not go ahead if the Seine was unsuitable.