The Cook Strait ferry Aratere is going to be lengthened so that it can carry more freight, vehicles and passengers.
Interislander, a division of KiwiRail, says the ferry will go to a shipyard in Singapore next March to be lengthened by more than 30 metres.
It says the ship will be cut in two and an additional section inserted,
giving the vessel 30% more freight and vehicle space, as well as more room for passengers.
The Aratere is scheduled to return in August, in time for the Rugby World Cup.