A country doctor has saved the life of a 13-year-old boy by using a household drill to drill a hole in his skull after a bicycle accident.

Nicholas Rossi was not wearing a helmet when he fell off his bike late on Friday while riding outside a friend's house in Maryborough, 170 kilometres north-west of Melbourne.

He hit his head on the pavement and was unconscious for 30 seconds, but recovered and appeared to be fine, his father Michael Rossi said.

But his mother Karen, a trained nurse, noticed a lump on Nicholas's head and decided to take him to the district hospital, where he experienced spasms and periods of unconsciousness.

Local GP Rob Carson recognised the symptoms of bleeding on the brain and realised he had just minutes to drill a hole to relieve the pressure.

Over the telephone, Melbourne neurosurgeon David Wallace walked him through the procedure.