Police said they had been alerted to the presence of the bodies in the town near the popular tourist destination of Interlaken at 7:00 am (1130 IST), but gave no further details.
Media reports said they were killed in a shooting incident and that police were carrying out a forensic search of a hotel balcony that overlooks the car park.
Residents in the area told the Berner Oberlaender daily that the shooting was linked to a family dispute, and that a man had first shot his wife and child before turning the gun on himself.
Police had blocked off a large area around the crime scene, and train cars had reportedly been moved into place to block visibility of the scene from a nearby school.