Erosion at Katiki Beach, between Palmerston and Hampden, has long been identified as a threat to a 7km stretch of State Highway 1 which runs between the Main Trunk rail line and the coast.
To counter the erosion New Zealand Transport Agency Waka Kotahi (NZTA) will next week begin placing more large rocks along the shoreline to absorb wave energy.
The key Otago freight and travel route had been vulnerable to coastal erosion for decades, NZTA senior project manager Jason Forbes said.
“Protection structures were first built in the 1970s, and we’ve continued to monitor and respond to changes along the coastline since then.
"Strengthening the coastline with rock armouring is the most practical and cost-effective option.”
In 2017, three high-risk coastal sites in this area were “armoured”, and a further 10 sites have been completed since then.
“Most of Katiki Beach will eventually require some level of protection to ensure SH1 remains resilient," Mr Forbes said.
Rock was being crushed and stockpiled offsite in anticipation of the work and the contractors would set up a site office and material storage at the beach’s northern rest area/truck stop.
The rest area will remain open for freight operators and others, but there will be single lane access through the site, entry from the north and exit from the south, with limited truck parking retained in the southern section.
Grant Hood Contracting has been appointed to deliver the $3 million project and was due to have crews setting up from Monday.
The work was expected to take 12 months.
