Bluebridge has cancelled sailings aboard the stricken Feronia ferry for a second day in a row.
An engineering fault discovered on Sunday night saw four sailings cancelled on Monday.
In a statement, Bluebridge said the issues were ongoing and warned more cancellations might be on the way.
Full bookings in the coming weeks meant passengers travelling with vehicles were unable to be rescheduled and were offered a refund.
Spokesperson Will Dady said Bluebridge apologised "unreservedly for the disruption to travellers' plans".
The company would work with passengers incurring costs due to ferry cancellations on a case-by-case basis.
There have been various cancellations of ferries across the Cook Strait recently, including both Bluebridge and Interislander-operated lines, due to faults and bad conditions.
A complaint laid with the Commerce Commission in February alleged both Cook Strait ferry operators are failing to operate with "reasonable care and skill after multiple mechanical failures and breakdowns".