Shark sighting disrupts WA triathlon

Around 100 athletes at a triathlon in Western Australia were ordered out of the water on Sunday after a shark was spotted during the Ironman 70.3 event in Busselton, about 200 kilometres south of the capital Perth.

Most of the individual competitors in the ironman event had already completed their 1.9-kilometre swim when the shark was spotted.

Those who remained in the water were ordered out by Surf Life Saving Western Australia personnel and the beach was closed.

Triathlon WA executive director Peter Minchin said the team event, which began about 90 minutes later, was reduced to a duathlon - cycling and running.

"The shark was spotted a fair way from the shore, but the Busselton surf lifesavers - who provide water safety at the competition - evacuated the water quickly," Minchin said.

"There was initial frustration, but they realised it was in the best interests of their safety," Minchin said.