The operator of the NCT has been fined €3m for failing to clear the testing backlog that has seen motorists forced to wait months to get their cars tested.
I was checking online recently to get cancellation booking, at as 23:00 there was 1 new slot, but after 00:30 a good number of new slots appeared
so I think you need to check online after midnight.
The new slots were mostly for 1 or 2 days later only.