The trust this week received a letter from Linz which gave the all clear, but it contained a few conditions, trust chairman Stephen Jeffery said.
"They are technical issues that need to be addressed and included in the agreement, then [we can] get the sign-off ... mostly minor legal things."
He said the new wording will be incorporated into the agreement and sent back to Linz to be signed off which should take "about a week".
Work could then begin immediately on the first 10km of the 34km trail from Alexandra to Flat Top Hill, on a mix of marginal strip and Department of Conservation land.
Tenders have already been let and a contractor was ready to start, with the work expected to take six months to complete.
The rest of the trail, to the Roxburgh dam, was reliant on negotiating land access.
"We are still negotiating with land owners over the rest of the trail but we are making steady progress," Mr Jeffery said.
Since its conception, there had been strong opposition to the trail from landowners along its path, with concern mostly over the negative impact it could have on the land.
Devon Miller, whose family farms at Shingle Creek, has aired issues, including the overall viability of the trail, insurance liabilities and people wandering off the track.
Because the trust failed to get easement agreements from some landowners, it opted to use the marginal strip where possible.
A recent survey of the Otago Central Rail Trail found it generated more than $12 million annually for the local economy, which is something the Roxburgh Gorge Trail Trust hopes its trail can do just as well for its local area's economy.
"To grow the economy we need more people and targeting tourists ... and the trail is the most obvious way to do that," said trail trust member and Alexandra businessman, Russell Ibbotson.
The Roxburgh trail would also link with the proposed Clutha Gold Trail.
That trail would stretch 73km from Roxburgh to Lawrence.
Both the Clutha Gold and the Roxburgh Gorge trails received funding from the Government under Nga Haerenga, the New Zealand Cycle Trail project.
A $2 million funding grant for the Roxburgh Gorge Trail was approved in September last year. The trail trust needs to raise the remaining $1.3 million.
