Pressure is mounting on the Transport Minister Leo Varadkar to ensure that the NCT consistency audit on various test centres is published immediately.
It comes in the wake of a TV documentary which revealed instances where NCT personnel passed cars that had previously been found to have serious defects, apparently in return for money.
Fianna Fáil's Transport spokesperson Timmy Dooley has written to the Minister for Transport requesting that he makes public this information.
Under the NCT consistency audit, the same vehicle was sent from centre to centre and tested to see if the same standards were met at each centre.
The audit was organised by the Road Safety Authority.