It could be days before stranded passengers bumped from interislander sailings are rebooked for crossings after a ferry break down, with priority being given to cyclone aid.

Its Kaiārahi ferry was taken out service after an engineering problem on Monday, leaving people stuck either side of Cook Strait.

To make things worse, right now the Kaitaki is only delivering freight after it lost power and got stranded at sea last month.

Executive General Manager Interislander Walter Rushbrook concedes the ships are old and they've had problems.