The main route between Hawke's Bay and Manawatū will be down to one lane for most of the week to make it easier to negotiate for heavy traffic.
The Saddle Rd, running from Ashhurst to Woodville across the Ruahine Range, became the main east-west route once the Manawatū Gorge road closed in April 2017.
The NZ Transport Agency announced on Monday it would close the lane going from Woodville to Ashhurst from 8.30am until 2pm from Monday, June 10, until the Saturday of the same week. It will be the first time the lane was closed on a Saturday.
Traffic wanting to head west during the closure can use the Pahīatua Track.
Agency regional transport systems manager Mark Owen said the closure was for work to raise seal on a roundabout in Ashhurst to make it easier for heavy vehicles to get around.
There would also be work around the summit of the Saddle Rd.
Closing the lane was the most efficient way to get the work done, he said.
Motorists heading east should still expect oncoming traffic, though, as construction vehicles will use the other lane.
The plan could change depending on weather, Owen said.