The digger that fell into the river while working on the Clutha Gold Cycle Trail near Roxburgh may never be retrieved.
Otago Regional Council environmental services manager Martin King said a member of his team was working with the trail contractors but "they [the contractors] are in a really, really tricky situation".
He said the digger, about 800m downstream of the Roxburgh Bridge, was in about 10m of fast-flowing water surrounded by 25m high banks in a "gorgey" area.
It was hoped a diver would be able to check out the digger this week, but that would depend on the weather.
Mr King said a decision on whether or not it could be removed would not be made until the diver had assessed the situation.
"From an environmental point of view there doesn't seem to be anything leaking at this stage but we will continue to monitor it.
"It will not be a preferred option to leave it there."
He said the contractor's insurance agent was involved in the process.
A further attempt to contact trail project manager Tim Dennis went unanswered yesterday.
