An unmanned drone has joined the search for bushwalker Prabh Srawn, almost one month after the Canadian man disappeared in the Kosciuszko National Park.
The drone is donated by Perth-based company COPTERCAM.
Company founder Hai Tran said he felt compelled to join the search as authorities scaled back their efforts, adding that he did not know about the missing 25-year-old until he was approached by Mr Srawn's family on Friday.
''They did offer to pay, but we weren't interested in that,'' he said.
Mr Tran said the mapping drone covered a square kilometre at a time, using an on-board camera to take about 200 photos which would later be examined by volunteers.
A fellow West Australian company, Cyber Technology, was also aiding the search efforts.
The donation coincides with a doubling of reward money by Mr Srawn's family, who are now offering $100,000 to anyone who can rescue or recover the bushwalker.
The increase was posted on social media on the weekend, days after the family announced a reward for the finder of the Canadian student, dead or alive.
The official Facebook page, titled ''Help Find Prabh Srawn - Missing Bushwalker'', emphasised the need for searchers to be experienced hikers, who register with the police and carry GPS equipment.
''We want everyone to be safe, all lives are valuable,'' it read. ''Please only hike if you feel you are well prepared.''
NSW Police have scaled back the search efforts and the rescue helicopter was withdrawn from the search last week.
The family of the Bond University student plan to stay in Jindabyne.
Mr Srawn was last seen wearing a white T-shirt and blue jeans. Police believe he may be wearing a red and black ski jacket including the words ''Frogg Toggs''.
He was last seen when he parked his car at Charlotte Pass Village, on May 13.