State Highway 2 through the Karangahake Gorge is to close for five days next week.

The highway will be closed between 9am and 4pm daily from Monday to Friday, weather permitting, while crews do rock-scaling and maintenance work.

The closure affects a 500m section near the historic rail tunnel bridge, extending towards Paeroa.

Property access will be maintained up to the closure points, but there will be no through access, NZ Transport Agency Waka Kotahi said.

NZTA said the work follows inspections during similar closures in August and will allow crews to remove larger unstable rocks and other necessary work.

Road users are being advised to travel through the gorge outside the closure hours or use State Highway 29 over the Kaimai Range.

NZTA Waikato area manager for asset and operations Andy Oakley said a full closure was necessary to keep workers and motorists safe.

“Rope-access technicians will be working directly above the highway and rocks may fall onto the road below,” he said.

The section of the Hauraki Rail Trail that passes through the old rail tunnel will also be closed while work is underway.

Emergency services and first responders are expected to have access through the closure area from Monday to Thursday.

Access on Friday may be restricted if conditions allow crews to complete rock armouring on a historic riverside retaining wall, which would require a large crane to be positioned across the roadway.

NZTA said other maintenance and resilience work will also be done where possible, reducing the need for future disruption.