Hundreds of swimmers have been pulled from an ocean event in Western Australia after a suspected 3 to 4 metre great white shark was spotted in the area.
Organisers of the annual Rottnest Channel Swim said on Saturday the event will continue, but swimmers within a 1 kilometre radius of the shark sighting were evacuated from the water.
Surf Life Saving Western Australia tweeted the co-ordinates of the shark sighting, noting it was "in the swim pack".
Those who were pulled from the water have had their competition number cancelled and while some of them chose to get back in and finish the race, their results would not be officially recorded, officials said.
A number of other competitors not affected by the evacuation are also said to have had withdrawn themselves from the race as a result of the shark sighting.
The Rottnest Channel Swim sees people swim a distance of around 20 kilometres from Cottesloe Beach through Gage Roads to Rottnest Island.