Extreme weather conditions in Australia have caused chaos at speedways on both sides of the country with events scheduled at Valvoline Raceway and the Perth Motorplex tomorrow night both cancelled.

The scorching 40C-plus temperatures have descended on Sydney and many parts of the state leaving promoters with no other option but to abandon the round of the Ultimate Sprintcar Championship.

By contrast, 111mm (or 4.5 inches) of rain lashed the Kwinana Perth Motorplex which was to see the next round of the World Series Sprintcars held tomorrow night.

In a first for the sport in Sydney, organisers have called off the event citing a duty of care to drivers, crews, officials and spectators.

It is expected to top 45C in western Sydney tomorrow with the overnight low anticipated to be no less than 35C.

After earlier announcing a revised scheduled, the Valvoline Raceway went one step further and cancelled the event.

“We have a duty of care to provide competition and entertainment in the safest possible environment for spectators, teams and our operations team and the reality is conditions are overwhelming here today, let alone tomorrow when the heat will actually increase again,” said managing director, Steven Green.

“Conditions are horrendous for any sort of activity, let alone motorsport where drivers and crash crew are dressed in fire-retardant underwear and race suits.

“We value our drivers and teams and naturally our spectators. This kind of oppressive heat can cause severe medical complications for people. There’s no decision to make when you consider everyone’s well being.”

Perth Motorplex Speedway Manager Gavin Migro announced that the latest round of World Series will not be rescheduled.

The Australian Kart Championships taking place in Newcastle this weekend remains on schedule.