If it’s good enough for French President Emmanuel Macron, it’s good enough for Bermuda’s Olympic champion Flora Duffy.

With doubts surrounding whether Duffy and the rest of the triathletes will be competing in the swim leg in Paris this summer after bacterial levels in the river Seine were deemed to be at dangerous levels during recent testing, French president Emmanuel Macron has been invited to prove that the water is safe by swimming in it alongside the mayor of Paris.

Swimming in the Seine has been illegal, bar a couple of exceptions, since 1923, with the river deemed too toxic for fish, never mind swimmers, but new facilities, including a water treatment plant that was opened on Tuesday, have been built to clean up the river with mayor Anne Hildago confident enough to invite top French officials to participate in a “big dive” to be staged in early July, just weeks before the Olympics.

Hildago has extended an open invite to Macron and International Olympic Committee president Thomas Bach as she grows increasingly confident that swimming will form part of the triathlon.

“We’re going to dive into the Seine and many volunteers have already come forward to come and dive with me and all the athletes who will be there,” Hidalgo said. “We’ll all be safe to swim in the Seine.”

For his part, Macron has said that he will take part, saying: "I'll do it, but I won't give you the date.“

In a recent report, environmental charity the Surfrider Foundation called the Seine “a particularly polluted spot” after it monitored bacteria levels for more than six months, concluding that athletes "will be swimming in polluted water and taking significant risks to their health.”

Olympics organisers have said that if pollution levels remain high the event could be rescheduled and, in the worst-case scenario, the swimming section of the triathlon would be cancelled.

The subject of water quality dominated the mayor's news conference on Tuesday, which was originally scheduled to unveil the cultural and sports celebrations to be staged on 26 sites across Paris during the summer.

More than 30,000 police officers are expected to be deployed each day during the Games, with 45,000 working during the opening ceremony on the Seine.