The construction of a new highway between Manawatū and Hawke's Bay is facing disruption from Covid-19 and wet winter weather.
But those in charge of the long-awaited route over the lower slopes of the Ruahine Range say, 18 months into the build, progress is good and it's still on track to open in late 2024.
Te Ahu a Turanga is a four-lane highway that will connect the lower North Island's east and west coasts.
The $620 million project will replace narrow, windy routes motorists have been forced to endure since slips closed State Highway 3 through the Manawatū Gorge in 2017.
From the Palmerston North end the new highway will cross the Manawatū River then head up a steep slope.
Speaking from a windy and wet construction site, project alliance owner interface manager Grant Kauri said it would feel familiar to motorists used to travelling on the Transmission Gully route, north of Wellington.
"It's very similar to TG - in fact, it's the same gradient, so everyone who's driven that will have the same experience here."
Cutting the climb up the hill involves huge earthworks.
"We've got about 1.8 million cubic metres [of earth] to come in here. We're currently sitting around 1.6 million," Kauri said of that section of the construction.
Wet weather had halted the earthworks on Monday. Photo / Angus Dreaver, RNZ
"It's starting to get some good shape to the alignment. We're probably around a 10 per cent gradient. That's the maximum you really want your larger vehicles to be travelling once this road is open and fully serviced."
When RNZ visited the site on Monday the wet weather had halted the machinery. It's churning its way through six million cubic metres of earthworks over the project's lifespan.
About 250 people are working onsite at the moment. It will peak at 300 during the summer construction season.
Supervisor for one area of the project Rob Graves said the elements weren't always kind for the earth workers, and on Monday it wasn't safe for them.
"We'll come back tomorrow when the weather improves.
"It's been very wet - wetter than usual. We're getting some fine days, but it's a pretty hard battle."
But it's not tools down completely.
"We're still working. The boys are out there in their wet gear tying steel, pouring concrete ... We're still working away."
Kouri said despite the challenges the construction team faced, the alliance - made up of Waka Kotahi NZ Transport Agency, construction and design companies, and iwi - still expected to finish on time and on budget.
"At the moment despite Covid and the impact that it has, not only on us as a project, but managing isolation and those types of things, there's an impact with our supply chain.
"So for us, our aim is still 2024, but we've just assessing that as it goes."
Some of the most impressive features of the new road are at the Manawatū end, where a pair of 300-metre-long bridges will ease motorists into their steep ascent towards the wind farm at the top of the hill.
One bridge is a viaduct over a wetland.
Piers for the other are appearing from the riverbed as workers operate from a temporary span next door.
