A five-metre beaked whale has been spotted just 20 metres offshore at popular Perth beaches this week, prompting a warning for beachgoers to be careful.

The Department of Parks and Wildlife says it is monitoring the whale, which has been sighted between Cottesloe and Fremantle beaches for several days.

Senior marine wildlife officer Doug Coughran said it was rare for such an animal to be seen so close to Perth shores, and it could be due to illness.

“We will continue to monitor the situation, but we will not intervene unless it comes ashore,” he said.

“Obviously we understand the curiosity beachgoers may have to get close to the animal, however we would like to remind the public that they should maintain a safe distance of 30m at all times in the water to ensure the whale’s wellbeing is not compromised.”

To report any sick or injured animals, call the Wildcare Helpline on 9474 9055.