An overdimension (or oversize) vehicle or load is one that exceeds one or more of the maximum dimensions allowed for standard vehicles. To drive an overdimension vehicle or load, you need an overdimension permit.
The standard dimensions of vehicles, loads and how much loads can overhang are specified in the Vehicle Dimensions and Mass Rule 2016(external link).
However, the law also provides for occasions when loads and vehicles exceed the standard limits. There are four categories(external link)(external link) of overdimension vehicles and loads.
In some cases you must apply to NZTA for an overdimension permit(external link) which sets a number of requirements including:
Bridges with weight/speed restrictions