Construction has started on the next stage of the Waikato Expressway, which will eventually link Cambridge and Auckland by a four-lane highway.
Transport Minister Steven Joyce on Thursday turned the first sod for the 12km-long Ngaruawahia Bypass.
Three sections of the 102km expressway have been completed, two are under construction and five sections are in the design stage.
Mr Joyce says the expressway, which is classed as one of seven roads of national significance, is on target to be completed by 2019 and the Ngaruawahia Bypass is an important part of the project.
Construction of the bypass is expected to create 300 jobs and be completed in 2014.