Organisers have cancelled next year's prestigious Ironman Asia-Pacific triathlon because of a scheduling clash with the Melbourne Formula One Grand Prix.
It is a significant blow to Australian triathlon, given the race had become a flagship event on the domestic calendar.
The triathlon was blindsided when the grand prix changed the date of the Melbourne race from April 3 to the weekend of March 19-20.
That meant a direct clash with the Ironman, which had already changed its date once to avoid the grand prix.
In a statement on the race website, organisers of the Ironman said the cancellation was due to factors outside their control.
Ironman Asia-Pacific chief executive Geoff Meyer said they looked at holding their race on the same day as the grand prix.
"The impact on the city, surrounding communities, roads and emergency services was not manageable for an event to be delivered in Melbourne to the level required for our athletes' safety and satisfaction," he said.
"Furthermore, Ironman athletes would be affected by increased travel expenses over these high demand dates in Melbourne.
"This was not an easy decision as the event has become a much-loved one by athletes and the Ironman community all over the world."
Like the grand prix, the triathlon has strong backing from the Victorian Government.
The Ironman Asia-Pacific championships were first staged in 2011 and feature a unique city-based course.
Most Ironman triathlons are held in regional areas because of the huge distances involved - a 3.8km open water swim, 180km cycle and 42.2km marathon run.
But the original race organisers successfully designed a course that starts with a swim at Frankston in Melbourne's Port Phillip Bay.
Most of the bike is on the EastLink tollway and the run is point-to-point, from Frankston to inner-suburban St Kilda.
Ironman Asia-Pacific organisers had suspended entries on October 1 once they learned of the scheduling clash.
