Over the past three weeks, six signs, four bollards and a 1km marker post have been damaged on the cycle and walking trail, leaving the trust behind the project ''absolutely disappointed''.
Clutha Gold Charitable Trust chairman Rod Peirce said the cost of the damage amounted to more than $5000 and appeared to have involved a four-wheel-drive vehicle.
''We're feeling absolutely disappointed ... It's a community project, done for the community.''
Two signs were left with indentations and splintered wood, while others were removed and tossed further along the trail or on the riverbank.
The vandalism happened on three separate occasions - between November 11 and 13, November 27 and 28 and some time this week.
All incidents occurred on a 10km stretch between the Beaumont bridge and the Talla Burn bridge.
''The community has been very supportive of the project. This is an aberration really.''
Mr Peirce said many local people had been out on the trail, cycling or walking.
About 10 days before the 73km trail between Roxburgh and Lawrence was officially opened in October, four bollards were taken out and thrown away along the picnic areas at the Beaumont end, he said.
Clutha Mayor Bryan Cadogan said he hoped anyone who had information would come forward.
''After such a great volunteer effort, and for something that means so much for the community, to have someone deliberately damaging [the trail] is more than disappointing.''
Acting Sergeant Steve Griffiths, of Balclutha, said police would be investigating and asked anyone with information to contact their local police station or anonymously through Crimestoppers 0800-555-111.
