New information about Malak Arok who went missing in 2012 has sparked a fresh search operation at Mount Ainslie, ACT police say.
The search, estimated to continue until sunset, is part of an ongoing long-term investigation into Mr Arok's disappearance.
"Today [Wednesday, October 23], approximately 30 members from ACT Policing, including specialist forensics, and AFP Search and Rescue will assist with the search," an ACT Policing statement said.
Specialist teams were covering a specific area of the Mount Ainslie quarry, in the hunt for evidence relating to Mr Arok, who was 35 years old when he went missing.
Climbing and abseiling in this area is believed to be prohibited.
One police member was seen scaling the mountain carrying piece of search equipment with a camera at the end, used to look in hard-to-reach places such as wombat holes.
Footage from ACT Policing, showed teams probing under logs and shrubs.
Police said they had identified an area of interest after reviewing information gathered from witnesses and "other sources of information".
Malak Arok, who has previously been referred to as David Abuoi and may have also used the first name Gabrielle, went missing on the morning of July 10, 2012.
He was last seen leaving the ACT Watch House, in Civic, wearing long dark-coloured pants and a long-sleeve dark-chequered shirt, police said.
"Mr Arok was a Sudanese refugee who came to live in the ACT in 2005," the police statement had said.
A police spokesman did not comment on what new information investigators had received or what evidence they expected to find.
They previously described him as being about 175 centimetres with a slim build, brown eyes and dark hair, which was short when he was last seen.
Police asked anyone who could provide more information about Mr Arok's disappearance to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website and quote 5093973.
