The stretch near the Royal Albatross Centre had been identified as a high-risk rural road, a Dunedin City Council spokesman said.
Work would take place from February next year.
The need for guard railing had been identified in the original planning for safety reasons, he said.
It was not part of the Peninsula Connection project.
Lane closures would be needed during installation of the railing.
Manual and automated traffic control signals would be in place.
The council spokesman said the work would be funded through the road safety budget and 52% of the cost would be covered by Waka Kotahi NZ Transport Agency.
It could take 20 weeks to complete.
