Gibbston couple Kelvin and Mary Lavell joined nine private landowners who previously granted public easements for the popular $1.4 million walking and mountain-biking trail.
The Lavells' easement links the eastern and western ends of the trail, association chairwoman Susan Stevens said in a statement last week.
"When the trail opened in December, we were unable to join the two ends of the trail along the river, so we approached Kelvin and Mary for help with an alternate route. They were keen, so it was just a matter of sorting the details and working through the paperwork."
Ms Stevens said the construction of the track was completed this month.
The Lavells were "chuffed" to contribute the final 100m to connect the Wentworth Bridge Loop to the Waitiri Loop via the Gibbston Highway Trail, which is a 1.2km track along the highway beside the farm fencelines.
The Lavells said they were "privileged to live in such a stunning place and now more folk can share the spectacular scenery and rich history from a river trail which ranks right up there for diversity and beauty".
Ms Stevens said the New Zealand Transport Agency, Opus International Consultants and Lakes Environmental donated and processed the necessary authorisations.
Southern Safety Services donated traffic management for the work along the highway and Treecare Southern Lakes donated arborist services.
Department of Conservation Wakatipu area manager Greg Lind said the directional signs for the junction were being made and would be installed this month.
