Watch: Drone footage shows scale and expanse of Wellington's new Transmission Gully motorway

The New Zealand Transport Agency is confident commuters heading in and out of the capital are now less than a year away from travelling on the Transmission Gully motorway, after several deadline delays.

After multiple challenges to completion of the 27km motorway caused by the Kaikoura earthquake, bad weather, difficult site terrain and the Covid-19 pandemic, contractor Wellington Gateway Partnership chief executive Sergio Mejia said he’s certain the project will be complete in September 2021.

“I can see the light at the end of the tunnel - can’t wait for September 2021,” he said.

Meija said he’s proud of the commitment of the thousands of crew that have worked on the project since it was established in 2014, with staff numbers now reduced to 570.

But weather events or seismic activity could still push the opening back further.

“So long as the weather looks after us, fingers crossed hopefully we should be okay,” Waka Kotahi project delivery senior manager Andy Thackwray said.

As delays stacked up, the budget has blown out from $850 million to $1.25 billion, and a wide-ranging Government review of the country’s first roading public private partnership is underway.

The complex landscape includes numerous streams which have been diverted and drainage through steeps slopes cut into the earth of up to 70 metres.

The project has involved 10.5 million cubic metres of earth moved, used 780,000 tonnes of rock for the road, seen three million plantings distributed and contractors working over nine million hours in total so far.

When open, the highway will save travellers around 11 minutes of drive time, compared to the existing coastal route.

“That’s what this road will provide … a much safer, reliable resilient journey,” Waka Kotahi’s Andy Thackwray said.

“It gives you an alternate road to the original coast road and you will get a traffic split between the two… you’ll definitely see less congestion as well,” he said.