Urgent repairs at the Moonlight Track, Arthurs Point, means the area will be closed intermittently for up to three weeks.
Queenstown Lakes District Council roading manager Ian Marshall said the closure would enable the construction of a gabion wall to stabilise a slip on the road.
The work was to have begun last week, but Mr Marshall said investigation was taking longer than planned.
"It could be two weeks [before we start the work], just until we understand fully the size of the problem.
"It extends a bit beyond the original area - the uphill slope is easy to define, the downhill bit is less so.
"The particular job we were going to do really only dealt with the uphill; it's looking like we might have to do something with the down slope as well."
It was not known what the work would cost, but Mr Marshall said it was a job that needed to be done.
"The soil is very susceptible to erosion and we want to protect it."
A section of the road above McChesney St was closed earlier this month allowing for stabilisation work to be carried out.
A large section of rock, estimated at 90-100 tonnes was brought down by an excavator the following day, after it had been affected by recent heavy rain and thawing.
The council contractors fixed the problem temporarily, by covering the area with a tarpaulin.
The next step was to fix the problem permanently, by installing the gabion wall.
"Setting the gabion at the bottom [of the slip] produces a more vertical piece of wall, and then we'll fill behind it, [and] cover up the exposed piece of slip at a better angle.
"It will protect it from [heavy rain].
"We are working with the residents as best we can to enable ongoing access to their homes but it is certainly going to inconvenience around nine properties," Mr Marshall said.
The work would be cleared at night, allowing residents to take cars through the site after 6pm and before 8am, he said.
"They're not happy - they're annoyed that the road's going to be closed and it's going to disrupt their plans.
"But if we don't close the road and fix it, there won't be a road in the future."
General track users may not be given access during the weekday but the track would be open for use at the weekends.
"We will try and maintain pedestrian access, which we will manage on request.
"The site will be effectively a construction zone and safety issues will apply."
Mr Marshall said the less disruption to "getting on with the business in hand during the week", the sooner the job would be completed.
