The hiker was identified as Kevin Arthur, 25, who had gone on the hiking trip with group but went missing near a river.
The Express was told that Arthur was one of 50 people, in the group called Fitness Walkers, on a one-way hike from Acono, Maracas to the Yarra river in La Fillette.
Members of the hiking group said that before the hike Arthur expressed fear over crossing the water.
It is believed that Arthur upon reaching the river left the group and decide to take an alternative route over the mountains rather than cross the river, but none of the hiking leaders were informed of this before he proceeded.
Members of Fitness Walkers said that before the start of the hike, the course was explained in full detail and safety instructions were given. with places to re-group identified and lifejackets given to all hikers.
Arthur showed no signs of struggling on the trail, the other hikers said.
The Express was told that Arthur was last seen wearing a flourescent green tee shirt and orange short pants.
Officers of the North Eastern Division Task Force, Defence Force, and fire services are engaged in search and rescue efforts.