KiwiRail says it is considering leasing a ship to help with the holiday rush as the Cook Strait ferries struggle to keep up with passenger demand.
A propeller came off the interislander ferry Aratere on 5 November in an area two nautical miles from Tory channel, leaving the vessel unable to carry passengers for at least four months.
Divers have been unable to look for the propeller due to strong southerly swell conditions.
A spokesperson says the company is also considering using the Aratere for carrying freight only which can be done with one propeller, or putting the ship into dry dock.
The replacement ferry might not be available until after Christmas.
KiwiRail has reopened bookings for a limited number of walk-on passengers on the Arahura and Kaitaki ferries until 19 December, but it says it is unable to book any more vehicles on its ferries.