A spokesperson said “confidence remains high” that sailings on the ferry will launch on January 13, despite some “small outstanding issues” to be dealt with.
They added: “The vessel has been performing well since she was handed over in mid-November.
“We are working towards an entry into service date of Monday, January 13 and confidence remains high that we will meet that target.
“We have a number of small outstanding issues to address and our view is that these should be prioritised over the next week to ensure we get the vessel into service on schedule.
“Some of these issues require support from third parties who were closed for the festive period, only reopening on Monday, January 6.”
It is believed the issues relate to ancillary systems that are not critical to general vessel operation but are needed for full entry into service.
The majority of the issues were identified between handover of the vessel and the start of the festive holidays.
The long-awaited vessel will sail to Brodick from Troon, with space for 852 passengers and 127 cars.
The ferry’s starting date came as it was revealed that the ageing MV Caledonian Isles – out of service for repairs for a full year – would not return to service until the end of March.
It will mean Arran will have a two-vessel service to Brodick with MV Glen Sannox from Troon and the Caledonian Isles from Ardrossan starting on March 28.