The Saddle Road will be closing for essential pavement repairs and maintenance works at various times from April 18 to May 14.
Waka Kotahi NZ Transport Agency regional transport systems manager Ross I'Anson said the work would significantly improve the condition and safety of the road.
"The narrow, steep and windy road is difficult to maintain and is a challenging environment to work on with the increased volumes of traffic since the Manawatu Gorge closure, so full closures are needed to ensure our crews have enough time to complete the work safely and to a high standard."
Subject to weather, the closures are scheduled for:
Sunday – Thursday April 18 to 22 (five night-time closures)
Monday April 26 (one night-time closure on Anzac Day)
Tuesday – Friday April 27 to 30 (four day-time and night-time closures)
Monday – Friday May 3 to 7 (five day-time closures)
Monday – Friday May 10 to 14 (five day-time closures)
"These times have been selected to minimise disruption to road users as much as possible while balancing the amount of work that needs to be completed," I'Anson said.
"We know the closures will cause some disruption and inconvenience to motorists, so we appreciate everyone's patience and understanding as we work to make the road safer."
Detours are via the Pahiatua Track.
The Saddle Road will be open to residents, Te Ahu A Turanga project teams and for emergency access at all times.
People should also be aware that wind turbine blades are being transported from Rangitikei St, Palmerston North, every night starting 10pm to the Turitea wind farm via the Pahiatua Track, from Sunday April 11 ongoing (weather dependent).
Motorists are advised to allow extra time for their journey and to be prepared for delays of up to 20 minutes over Pahiatua Track.