The NZ Transport Agency Waka Kotahi has announced Transmission Gully will finally open by the end of this month.
It was meant to be completed in April last year but was plagued by delays. The opening date then got pushed back to September, then December before Waka Kotahi conceded the project wouldn't be finished in 2021.
The project, an upgrade of State Highway 1 between Wellington and Levin, was first announced in 2009 by then-Transport Minister Steven Joyce.
Waka Kotahi transport services general manager Brett Gliddon says the agency is confident Transmission Gully is now in a fit state to open.
"We have not been prepared to compromise on the road's safety, however, all of the critical safety assurance tests have now been completed to a standard that gives us confidence the road will be a safe, reliable route for motorists between Wellington and the rest of the North Island," he said in a statement on Thursday.
Construction on the 27-kilometre road began in 2014 and set the taxpayer back $1.25 billion - having only meant to cost $850 million.
The chair of Waka Kotahi's board, Sir Brian Roche, said instructing the contractor to open the road by the end of this month was "pragmatic and considered". Sir Brian had earlier apologised for the opening delays.
"Waka Kotahi has been committed to finding a pragmatic solution that ensures we are doing everything we can to open a safe motorway while meeting the public expectations for it to be open for use as soon as possible and to ensure we safeguard good use of public money," he said on Thursday.
Gliddon acknowledged it was disappointing for the road not to open in December ahead of a busy holiday season.
"However, we acknowledge the builder has worked extremely hard over summer and while there are still a number of quality assurance tests in the original contract that has not been finished and there is paperwork that still needs to be completed, we don't believe they are critical factors that should prevent traffic from being able to use the road."
He said the builder, Wellington Gateway Partnership, has been told Waka Kotahi expects the road open as soon as possible and "that responsibility now sits with them".
Gliddon said, however, Waka Kotahi wouldn't be announcing a specific opening date - as it wouldn't with any other new motorway opening.
"When people drive Transmission Gully we know they'll enjoy the stunning views through the Wainui Saddle and appreciate the scale of the complex engineering required to build this road through some of the most challenging terrains in New Zealand.
"Most importantly, it is a safer and more resilient route than the coastal route people are currently using."
