Ten new four-lane state highways pledged by National are a "generational lift" in the network to provide for economic and population growth, Bill English says.
Watch National's leader Bill English speaking to Morning Report's Susie Ferguson:
Mr English told Morning Report's Susie Ferguson the roads would complete the "obvious spine of the country", with four lanes from Whangarei through Auckland down to the Kaimai Ranges, taking in Hamilton, and in the lower North Island, from Sanson through to Wellington.
National has said the $10.5 billion cost of the projects would be met through the National Transport Fund and public-private partnerships. Some of the spending, such as for the East-West Link, has already been announced.
"This is nation-building. This is a generational lift in our roading network alongside the public transport investments and they will help underpin the economy," he said.
"This is getting ahead of the curve."
The complaint in the past had often been that New Zealand had waited too long to build roads, Mr English said, and the policy was about catching up and moving a little ahead of growth.
The roads would take about 10 years to complete, he said. They would be considered roads of national significance, so could be put through a rapid consenting process.
Despite Labour's rise in the polls since Jacinda Ardern took over the party leadership, Mr English said there wasn't a mood for change.
He said National was talking about policies and laying out plans for the next three years, while Labour wasn't clear about what its policies on tax and climate change actually meant for people.
"There's challenges we're gearing up to meet - the transport challenge, how to deal with our most complex and vulnerable families, how to underpin a growing economy.
"Labour's a lot less clear ... They seem to be announcing policies but not sure what they mean."
Mr English said National must lift its support if it was going to form a "sensible government" after the election and it was great to see people engaging with what was becoming a clear choice.