THIS fiery streak in the sky amazed Perth beachgoers at sunset as a suspected meteor plunged into the ocean off the WA coast.

PerthNow reader Gavin Trought snapped the 'fire in the sky' as it appeared over Cottesloe, Perth, just before sunset on Friday, with remnants of the phenomenon still visible in the sky this afternoon.

"The weird streak in the sky as seen from Cottesloe last night. I noticed it just before sunset," he told us.

Perth journalist Pip Moir also posted the photo she took at Cottesloe Beach to Twitter shortly after 6pm as puzzled onlookers debated what caused the colourful phenomena.

Daniel Jongue, manager at The Naked Fig Cafe, said he noticed "something on the horizon'' just before sunset.

He said the fiery trail took about 20 minutes to dissipate.

"It looked like vapour. It was red, orange and yellow and quite beautiful,'' he said.

A spokesman for the Bureau of Meteorology said the weather bureau's radar would not pick up a fast moving object like a meteor.

Perth Observatory and Astronomy WA could not be reached for comment.