Man fights for life after Perth blaze

An explosion is believed to have sparked a fire in North Perth that has left a man fighting for life in hospital.

The blaze destroyed a ground floor unit in Charles St about 10.40am on Saturday with fire crews rushing to the scene.

Witnesses told media they saw a large bang and smoke billowing out of the unit.

A man in his 40s was taken to the Royal Perth Hospital and is now in a critical condition.

The cause of the blaze is unknown, but believed to be suspicious, and the Police Arson Squad is investigating.