Motorists will be able to use the road through the Manawatu Gorge midway through this week, earlier than scheduled.
State Highway Three through the gorge was closed by slips on 18 and 31 August last year and another in October, which brought down 370,000 cubic metres of hillside.
From mid-week, one-way traffic from Woodville to Ashhurst will be allowed through during the day, and there will be two-way traffic at night, controlled by lights.
In May, the Transport Agency estimated the cost of clearing the slip, building new bridges and maintaining alternative routes would be up to $20 million.
The closure of the gorge route is estimated to have cost the regional economy $62,000 per day.