Head injuries threaten Vic boy's life

A four-year-old boy has suffered life-threatening head injuries in an incident at a Melbourne home.

Paramedics were told that the boy suffered head injuries after jumping on a bed in a Glenroy home on Friday afternoon, an Ambulance Victoria spokeswoman said.

But police say local detectives are investigating.

"The boy suffered life-threatening injuries," a Victoria Police spokeswoman said.

"Detectives are on the scene of the incident now."

The boy was taken to the Royal Children's Hospital in a critical condition.

The police spokeswoman said she had no information on who was with the boy at the time or how he came to be injured.