The region's mayors have welcomed New Zealand Transport Agency's announcement of a permanent fix for State Highway 4 Parapara between Whanganui and Raetihi.
There are a number of major work sites on the road, including one at Te Ore Ore where 400m of the road was destroyed in a slip in October last year. A temporary road around the site has been operating since December.
Whanganui mayor Hamish McDouall said NZTA's decision was welcome because "it's not just the slip, the whole route will be repaired".
"It was pretty good to get that temporary road in before Christmas," McDouall said.
"I thought it was one of the most remarkable feats of engineering and now they are going to reinstate a permanent road.
"It's still a difficult route with geographical challenges. It's such a key route for freight and people from Whanganui. Less so for tourism actually, we only get about 5-6 per cent come down SH4. But nevertheless, for people who live on the road, emergency services, for general connectivity between Whanganui district and Whanganui city it is amazing.
"The key thing is they are doing the whole route.
"It's a good road to be secured for the future. Many times I've told NZTA and city transport officials, when SH1 closes, SH4 becomes the main route north and south for the country."
Ruapehu mayor Don Cameron said three main land lots had been looked at for the highway and the best one had been chosen.
News that the land acquisition has been made was "tremendous", he said.
"I have to say it's probably a model of how a government department can work with local councils, iwi, communities and landowners to come up with a solution really quickly," Cameron said.
"All I can say is congratulations to NZTA, they've done a fantastic job, they really have."
Cameron commended the support for the project from iwi and Ātihau Corporation leading in the swift land transaction.
"The other point is it's really good news in the midst of not a lot of good news for people. Knowing that road will be pretty resilient and bought right up to speed in time for next winter. It's what we have been waiting for some time."
The new road will follow a similar path to the temporary route around the Te Ore Ore slip, crossing a stabilised section of the slip, and was chosen after a range of routes were assessed.
NZTA regional transport systems manager Ross I'Anson said the assessment took into account cultural heritage, impact on property owners, ease of construction and landscape protection.
"The road is in a difficult environment so any option would need to strengthen the highway's resilience so it can better withstand the challenges of the unique topography and severe weather," I'Anson said.
It was a vital route for locals, travellers and freight, he said.
The chosen option will improve ground stability by lowering groundwater levels to help guard SH4 against future slips.
Further work on detailed design, resource consents and property discussions is under way and work will begin soon to remove water using wells and pumps in preparation for construction, expected to start in the summer of 2021.
"We would like to thank Ātihau-Whanganui Incorporation and mana whenua Ngāti Rangi for their generosity and support throughout the process of building the temporary road and looking at options away from the existing road," I'Anson said.
"We look forward to continuing to work alongside them as we move to the next phase."