Motorists crossing the Kaimai Range are being urged to plan ahead, with State Highway 29 set to close overnight for two nights later this month.

The highway will be closed between 8pm and 3am on Sunday, September 13, and Monday, September 14, reopening to traffic each morning.

NZ Transport Agency Waka Kotahi (NZTA) said in a media release that the closures are needed so crews can safely complete the final stage of a programme designed to improve safety and resilience at the Ruahihi Bluffs site, near the Ruahihi Power Station.

Bay of Plenty area manager Sandra King said the work follows urgent rock-scaling operations carried out in late 2025 and the installation of a rockfall protection system that began earlier this year.

“Following urgent scaling work completed in late 2025, crews began installing a rockfall protection system in February this year to help prevent falling rocks from reaching the state highway,” King said.

“We’re now returning to install the final components of the system, including two steel trusses weighing 1500kg each. Once in place, the rockfall protection system will provide an additional layer of protection for people using this important route.”

The installation will require a 100-tonne crane and a large worksite, making a full road closure the safest option.

“The installation requires a 100-tonne crane and a large worksite. Given the size of the machinery and the nature of the work, it is not safe or practical to keep the road open,” King said.

A further night of stop-go traffic management will be in place at the Ruahihi Bluffs on Friday, September 18, between 8pm and 3am while the site is dismantled. Significant delays are expected, with traffic allowed through on the hour.

NZTA will also use the overnight closures to complete other maintenance activities along the corridor, including work associated with the Ōmanawa Bridge replacement, drainage improvements and road surface maintenance.

Closure points will be established at the SH29/SH24 and SH29/SH28 intersections on the Waikato side of the range, and at the SH29/Redwood Lane/Kaweroa Drive roundabout on the Bay of Plenty side.

Residents will continue to have access to their properties from the relevant side of the closure, although delays are expected.

A local detour around the Ruahihi Bluffs site will be available via the Ōmanawa, Peers and McLaren Falls roads, while emergency services will be given access through the worksite when required.

Motorists are being warned that wider detours are lengthy and will add significant travel time.

Northbound traffic is advised to use SH2 via the Karangahake Gorge, SH24, SH27 and SH26. Southbound traffic can travel via SH5, SH30, SH33 and SH2 through Rotorua, while light vehicles also have the option of using SH36.

King acknowledged the disruption but said the long-term benefits would outweigh the short-term inconvenience.

“While there will be short-term inconvenience, this work will help provide a safer and more reliable route over the Kaimai Range for years to come.”