Qld gas blast deliberately lit, say police

A Cairns man is fighting for life in hospital after allegedly causing a gas bottle explosion at a north Queensland home.

Seven News reported on Friday the 39-year-old was in a critical condition in Royal Brisbane and Women's Hospital.

Police believe he triggered the blast on Thursday afternoon by using a lighter and gas cylinder, causing the roof of the Kewarra Beach house to lift off its rafters.

He and his mother, 65, suffered extensive burns.

Seven said she was released from hospital on Friday.

Queensland Police say the home is being treated as a crime scene.