The Cook Strait ferry Aratere will undergo a major refit next month in Singapore.
The ship will be cut in half and a new 30-metre long mid-body and new bow installed.
Ferry owner Interislander says a former Straight Shipping and Bluebridge ferry has been leased for five months to cover for its absence.
The $40 million refit will add space for about 300 more passengers, increase the ship's vehicle capacity by more than a third and its space for rail freight by more than a quarter.
Aratere is due to return in the second week of September, in time for the Rugby World Cup and the seasonal lift in rail freight.
