Multiple sharks have been spotted swimming near a large, smelly whale carcass that has washed ashore at a popular capital city beach.
Hundreds of onlookers gathered at Perth's City Beach on Monday after surf lifesavers found the dead animal about 7.30am and raised the alarm.
"It's sad, they're such a beautiful animal," local David Jones told AAP.
Local authorities closed the beach for several kilometres in each direction of the carcass, which appeared to be about six metres long.
Multiple sharks have been spotted in the area, including a five-metre great white.
"It is possible the carcass will continue to act as an attractant that could lead to sharks coming in close to shore along this stretch of coast," the Department of Primary Industries and Regional Development warned.
"People should exercise additional caution."
The alerts come 10 days after 63-year-old Greg O'Neill was killed in a shark attack while swimming close to shore at Sorrento beach, about 12km north of City Beach.
Town of Cambridge mayor Gary Mack said it was important members of the public took heed of the warnings.
"This is not a time for taking risks," he said.
Mr Mack said authorities were assessing the carcass and it was likely to be removed from the beach on Tuesday.
"It seems at this stage the plan will be to remove the carcass on the back of a truck and take it to a landfill site," he said.
The other option is to tow it out to sea, but Mr Mack said that may prove difficult.
"There's a bit of surf down there, and it's rocking back and forth and appears to be wedged on the sandbar," he said.
Mr Jones said several dead whales had washed up on the same stretch of coast in the previous decade.
"I think they've buried them in the past," he said.
Many onlookers took selfies in front of the massive carcass, while others held their noses to protect themselves from the stench.
The silhouettes of sharks could be seen in the waves swimming up and down the coast.
