Two areas of "unstable rock" - one of which was a remnant of a major rock fall 10 years ago - have been discovered at the Nevis Bluff.
New Zealand Transport Agency Central Otago Area manager John Jarvis said the two areas had been assessed as posing a "potential hazard" to road users and the agency was moving to stabilise the areas before the risk became greater.
The work would begin at the site, on State Highway 6 between Queenstown and Cromwell, on February 8.
It was expected to be completed by March 19.
The rock fall in September 2000 closed the road for two weeks.
The remnant of that fall would be removed by drilling and blasting, while the second area of concern would be stabilised using rock bolts to help ensure the long-term stability.
The work was part of the agency's continuing monitoring of the Nevis Bluff.
"Because of the difficulty and unpredictable nature of the drilling and blasting work, and for safety reasons, road closures can be expected from Monday to Friday throughout the course of the work," Mr Jarvis said.
There would be road openings every hour, on the hour, between 8am and 5pm and motorists were advised to time their travel with a road opening.
Between the hourly openings, traffic would be cleared every 20 minutes.
There would be closures of up to one hour during the course of the work to allow for blasting operations, he said.
"At this stage, only a handful of blasts are expected over the six-week stabilisation programme."