Three men are in hospital after falling more than nine metres from a balcony in southwest Calgary on Saturday.

Calgary police said they're investigating, along with officials from the planning department.

The incident took place around 3:15 a.m. at a four-plex on the 1800 block of 23 Avenue S.W. The men plunged to the ground after the railing on the balcony gave way.

One man sustained what police called a "serious head injury," but it's not believed any of the injuries are life-threatening.

The investigation is focused on what happened leading up to the incident and trying to determine why the railing gave way.