The Interislander has three ships – Aratere, Valentine and Kaitaki. But Aratere is dry-docked in Sydney for maintenance.
Aratere was originally sent to Sydney in September 2021 for mechanical issues, but just weeks after it returned a broken part of the engine started causing abnormal vibrations onboard.
Interislander executive general manager Walter Rushbrook told the Herald he expects Aratere to be back in operation sometime around Anzac weekend. However, no sailings with a vehicle are available currently until mid-May.
"We are maximising use of capacity on Kaitaki and Valentine to meet demand while the ship is away," Rushbrook said.
"Currently there is very high demand for passenger bookings and little space available. We have plenty of capacity for foot passengers."
Bluebridge spokesman Will Dady told the Herald the ferry has been operating at close to, or at capacity for "quite some time" due to strong freight and passenger demand.
Dady declined to say how long the ferry had been operating like this for, or when it was predicted to ease.