The Driver and Vehicle Agency (DVA) shared the worrying results in an internal letter, explaining that the safety of staff and customers “is of the utmost importance”.
The discovery of cracks in a lift at Larne MOT Centre in November triggered a wider investigation.
Questions surrounding the safety of test centres in England, Wales and Scotland remain unanswered.
Despite test centres failing to communicate cancellations, the Department for Infrastructure (DfI) has advised drivers to attend their scheduled tests unless contacted by the DVA.
Motorist Carla Lockhart tweeted about the confusion: “Concerning that there appears to have been a breakdown in communication over the closure of testing centres.”
Meanwhile, Pamela Telford told how her insurance company won’t cover her to drive her car once her MOT certificate expires – she arrived at the Coleraine centre to learn only retests were being carried out.
OUR BIGGEST EVER BLACK FRIDAY SALE
The DfI said the DVA “sincerely apologises for the inconvenience caused” and explained that they are working to resolve the issue as soon as possible.
News of the faulty lifts and reduced testing comes as statistics were revealed showing half a million cars had a late MOT test in January.
Cash-strapped motorists defer tests due in the first month of the year, despite 70,000 (14%) cars eventually failing with a dangerous fault.
The maximum cost for an MOT test, £54.85, pales in comparison to the £1,000 fine charged for anyone caught driving a vehicle without an MOT.
Book your MOT test at an RAC Approved Garage.
Inspections by the lift supplier confirm that they had designed a “remedial repair” and work is already under way. The firm are responsible for the maintenance and regular inspection of the equipment.
Limited tests are being carried out at most MOT centres while repairs and inspections continue.
The DVA hope that remaining inspections and precautionary checks will be completed by Friday 24 January.
- MOT checklist and comprehensive guide
- 12 simple car maintenance checks you should definitely be doing
- New MOT rules – how do they affect you?
- How giving your friends a lift can lead to a hefty fine
- Motor industry calls for MOT exemption to end over fears of unsafe cars on the road
A DfI statement said: "As and when test centres have been inspected and any necessary repairs completed, they will immediately become operational.
"Boucher Road, Cookstown and Newbuildings test centres are now fully operational and all MOT tests are being carried out."
Immediate tests will be prioiritised and a number of test centres will open on Sunday to deal with the workload.
Are you affected by cracked lifts in Northern Ireland? Do you worry that the equipment at test centres in the rest of the UK are in a similar state? Let us know in the comments…
Is it illegal to drive without shoes?
Get the answer and more useful driving content sent straight to your inbox.
