National is promising to revive an old pledge to extend the Waikato Expressway if elected in September.
Party leader Todd Muller said the four-lane motorway would run between Cambridge and Piarere, north west of Tirau.
It would connect the Cambridge section of the Waikato Expressway to the intersection of State Highway 1 and State Highway 29.
The previous National government had started work on the road, but the coalition government pulled the plug on the project in 2018.
Muller says that made no sense.
"After three years of no progress we need to get on with this expressway as soon as possible to ease congestion, save lives, create jobs and stimulate our economy", he said.
Residents living near the intersection have previously raised safety concerns about the existing road between Cambridge and Piarere.
Construction of the 16-kilometre extension, which is estimated to cost about $570 million, would begin in the party's first term, Muller said.