A new freight study shows transporting goods by trucks will increase by 50 percent over the next 30 years.
That's a reduction on a 2008 report that put the figure at up to 75 percent.
The Ministry of Transport report says at present, 70 percent of freight is moved by road, 16 percent by rail and 14 percent of goods are transported on coastal shipping.
Road Transport Forum chief executive Ken Shirley said the main reason for the overwhelming use of trucks was the obvious flexibility of road transport, compared to rail and shipping.
Transport Minister Gerry Brownlee said the study showed the $12 billion investment in the Roads of National Significance couldn't have come at a better time.
The Automobile Association's general manager of motoring affairs, Mike Noon, said it won't be a case of more trucks, but better trucks on the road over the next 30 years.
"Trucks which are able to carry 50 tonnes instead of 40 tonnes. The trucks look very similar, they have a slightly different axle configuration so they don't damage the roads, but it means that you are carrying 20 percent more load for the truck."