The additional funds would pay for stonemasonry, diggers and the transport of schist rock.
Arrowtown Village Association (AVA) track committee member John Mowat said he, three volunteers and stonemason Keith Hinds, of St Bathans, finished the wall with like-for-like stone repairs last week.
Work was performed in consultation with the New Zealand Historic Places Trust, Mr Mowat said.
"It was only when we put up the scaffolding that we realised the full extent of repairs.
Those repairs have finished, but we've still got 200m left to complete the 15km trail as an all-weather trail from Macetown to Arrowtown.
The section being worked on is part of the 3000km Te Araroa walkway, from Cape Reinga in the north to Bluff in the south.
Donations to help finish the trail can be made by calling AVA chairman Richard Newman on (03) 442-1616.