Police hold grave concerns for the 52-year-old's well-being and are calling for any new information about his whereabouts from the public.
Mr Gourlay was last seen on December 20 when he was dropped off on Kaikorai Valley Rd at 8am.
He spent December 18 with family and they became concerned when he could not be contacted on his birthday, December 23.
He was reported missing on Christmas Day.
Sergeant Nathan White confirmed yesterday Mr Gourlay's bank accounts had remained untouched.
Since he was reported missing, police and LandSAR volunteers had carried out extensive searches of the Kaikorai Valley and Ravensbourne areas and they were "pretty confident we have cleared them well''.
"They have put in some big days,'' he said of the searchers' efforts.
No traces of Mr Gourlay had been found.
"We need new information for areas that he might be,'' Sgt White said.
"We have had a lot of calls about him and, generally, they are all investigated. But we are at the stage where we just need information about where to search.''
Police remained in regular contact with his family, who were "racking their brains'' to provide new information.
"They have been great,'' Sgt White said.
"Even though it's a tough time, they have been really good with the information that they have been coming through with.''
Police were reviewing some information which was received during recent days, including trawling CCTV footage of apparent sightings.
However, mystery still surrounded Mr Gourlay's disappearance.
Police had found no evidence to suggest his disappearance was suspicious, but deep concerns for his safety remained.
"We have always been concerned,'' he said.
"There's no change in that.''
● Anyone with information that can help should contact Dunedin police on 471-4800. Information can also be provided anonymously to Crimestoppers on 0800 555 111.
