Motorists using the popular thoroughfare between Beaumont and Raes Junction on Wednesday morning can expect some delays and explosions along the way.
Blasting work will be carried out to remove rock bluffs above a section of the highway as part the Raes Junction safety improvements project.
It will ease a series of tight curves on the stretch of road that links South, West and Central Otago which has a history of crashes.
A New Zealand Transport Agency spokesman said motorists using that part of the highway could expect an extended delay of up to 30 minutes between 10am and 10.30am.
"The drilling and blasting work is essential to make room for the new road alignment.
"The NZTA regrets any inconvenience to road users and appreciates their patience while this essential safety work is carried out."
The delays are subject to weather conditions.
As well as the extended delay due to blasting, work will continue between 8am and 6pm Monday to Friday, with one-lane, one-way traffic being maintained at all times.
Minor delays may be experienced at critical stages of the works.
Excavation of the area is expected to be completed by Easter, with pavement construction and sealing work starting in spring.
