The section of State Highway 1 closed since the Kaikoura earthquake in November 2016 is to reopen after more than a year of major roadworks.
SH1 between Picton and Christchurch will reopen for night-time travel from the end of April for the first time since the Kaikoura earthquake, which caused major damage to the route.
"People driving between Picton and Christchurch can look forward to easier journeys," Transport Minister Phil Twyford said.
"Critical safety work on the coastal corridor is almost complete, with the North Canterbury Transport Infrastructure Recovery crew making a massive push over the next four weeks to reach this milestone."
The reopened highway, along with the alternative routes via state highways 63, 6, 65 and 7 through Lewis Pass, will provide two 24/7 options for travel around the upper South Island.
Twyford said it would bring social and economic benefits back to the region.
"This news will be welcomed by communities, the freight industry and everyday Kiwi drivers alike."
NZ Transport Agency earthquake recovery manager Tim Crow said stopping or camping would still not be allowed in the two most earthquake-damaged areas just north and south of Kaikoura.
"Stopping is only allowed where signposted as a 'safe stopping' zone."
A short closure of the section south of Kaikoura is planned for mid-April to have the road ready to be opened at night.
With more wet weather expected through autumn crews would continue to monitor the state of the road.
"In the event of persistent heavy rainfall we may close the road as a precautionary measure – this can happen day or night," Crow said.
Despite the road re-opening, work would continue on the corridor throughout the year to improve safety and resilience.