The Queenstown Lakes District Council transport managers and engineers concluded the road would take at least four to five weeks to restore before being open to traffic beyond the 100-metre drop caused by the slip.
Part of the road, built in 1863, collapsed about 18km from the Coronet Peak turn-off on Tuesday after heavy rain and snow in the area. The collapse left 12 households and seven tourist operators pondering how to access home or get customers to the other side of the "Devil's Elbow".
QLDC transport manager Denis Mander said the council proposed an immediate start to work and seven-day working week to repair the road.
"We are looking at a proposal to cut into rock wall on the inside curve of the slip area to create a road bench and to rock bolt as necessary."
The repairs would need Otago Regional Council approval as engineers proposed rocks be disposed of in the Shotover River below during work.
"We did explore alternatives, such as lowering the road, bridging or completely realigning the road, but discounted these because of combination of engineering feasibility, cost and time to implement," Mr Mander said.
Wolfgang Ickenroth, of Queenstown Heritage Tours, described the reconstruction period as "appalling" and accused the council of wasting money.
Mr Ickenroth had spoken with local engineers who said the job could be done in five to seven days.
"We run 10-20 customers on a daily basis ... This is our livelihood."
Mr Mander said the repair was also being considered by the Historic Places Trust.
