The condition of a Brisbane teen left fighting for life after being kicked in the face has worsened.

On Friday night the 17-year-old smashed his head on bitumen outside Redcliffe McDonald’s following the alleged assault by an 18-year-old man , police said.

He had been stable but critical throughout Saturday, but his health has since deteriorated, a Royal Brisbane Hospital spokeswoman said on Sunday afternoon.

The boy was put in an induced coma at the scene of the attack, Queensland Ambulance operations supervisor Brad Hardy said.

It was “terrible to see a young life potentially destroyed” in such a manner, he said.

The alleged attacker has been charged with grievous bodily harm and is due to front Redcliffe Magistrates Court on Monday.

Police want to speak to a witness who provided first aid to the boy and are appealing for dashcam footage.