During the closure crews will be removing overhanging material and unstable rock caused by a slip near Kakatahi, 50km north of Whanganui.
An NZTA spokesperson said the work must be done during the day for safety and visibility reasons, and the road is too narrow for vehicles to use during repair work.
Lyn Griffin-Chappel, who co-owns Angel Louise Cafe in Raetihi, said she'll be pleased to see the work start.
"It needs doing because it's a pretty dangerous road as it is.
"I don't think it's going to make too much of a difference to my business and I'd rather see the road fixed and safe instead of constant rock falls or people getting hurt.
"It's been a long time coming and there's still a lot to go but this is a step in the right direction."
Heartlanz Motor Inn's Damon Shaw said the repairs will be good in the long term.
"For Raetihi it has to be good because the road needs to be done.
"We're having some major renovation work at Heartlanz and a few of the contractors are coming over from Whanganui, it means they have to leave a bit earlier and stay for a few days."
Road users are advised to check NZTA Central North Island's Facebook for any updates on the closure or if work is postponed due to weather.
