Martin Colwell, a search manager with Lions Bay Search and Rescue, said yesterday the four were among a group of five hikers who vanished Saturday afternoon.
The search continues for the fifth person.
He says it appeared the group was walking on a cornice when it fell from under them and swept them down the mountain side.
The group was hiking with a sixth person on Mount Harvey Saturday when he fell behind.
Police say when the man made it to the summit he couldn't find his companions and alerted police.