State Highway 1 south of Wellsford reopened last night after a rockfall on Tuesday forced its closure.
Geotech engineers gave the all-clear for the road through Dome Valley between Wayby Valley Rd and Wilson Rd which is the most direct route between Whangārei and Auckland to re-open.
Motorists were forced to use SH16 for the duration of the road closure.
SH1 on Dome Valley has had two other closures already this year due to slips - one in February after Cyclone Gabrielle that lasted 76 days.
Maintenance crews are building a 40-metre debris wall to prevent future loose material from falling onto the road.