Police remain at the scene of a house fire in a dense suburban neighbourhood in Perth’s south.

The alarm was raised for the house fire in Spearwood about 6am on Monday, triggering a major emergency response as the blaze ripped through a home on the corner of the main artery of Phoenix Road.

Police have locked down the scene and shut traffic off to a section of Phoenix Road, while the home has been cordoned off with red and yellow tape.

Four fire units left the scene just before 8am, while a heavy police presence remains, with the cause of the fire still unknown.

It’s the second fire at the property in the past week, with crews responding to a blaze in its rear shed sparked by lithium batteries on Monday last week.

Detectives from the arson squad were seen at the property following the blaze.Camera IconDetectives from the arson squad were seen at the property following the blaze. Credit: Ian Munro/The West Australian

The recent fire is understood to have started in an external sleep-out, with a neighbour at the rear of the property calling triple-0 while another went to the door to alert occupants.

Detectives are still working to determine what sparked Monday’s fire, with the arson squad attending to make further assessment, a police spokesperson confirmed.

Several distressed members of the public arrived at the scene, joining a small gathering at the front of the house next door.

More to come.