State Highway One north of Whangarei has opened fully to traffic - more than a year after the disastrous rain-storm that caused a huge slip at Maromaku.
Contractors have been working at the site since last July, when a 10-metre section of the winding road slumped, closing the highway for a week.
The Transport Agency says the $3 million rebuild would make the main route between Whangarei and Kawakawa more resilient in heavy rain.
To stabilise the site, contractors had to drive 39 concrete piles 21 metres into the ground, and move 3000 tonnes of earth for a retaining wall.
The agency says new safety barriers and culverts will improve drainage on the hill, and make the road safer.
It says it is grateful for the patience of motorists who have had to drive slowly while work's been in progress.