All MoT tests for cars and light vehicles in Northern Ireland have been suspended with immediate effect.
The Driver and Vehicle Agency (DVA) said inspections of lift faults in test centres did not provide “sufficient assurance” on the effectiveness of ongoing repairs.
MoT exemption certificates are being issued so motorists are able to drive.
The DVA said anyone scheduled for a car or light vehicle MoT on Tuesday “should not attend”.
Test on heavy goods vehicles and buses will continue.
Paul Duffy, chief executive of the DVA told BBC News NI: “This is hugely embarrassing for the DVA.
“I think we have a fairly good reputation and this is something that has tarnished that reputation.
Mr Duffy said he had sought assurances from the contractor responsible for supplying, maintaining and servicing the lifts that they were safe to use.
He said: “We were given that assurance when the initial repairs were taking place, but that assurance then was not forthcoming from the contractor this evening on further inspections of lifts today.
“On that basis we had no option but to suspend the tests.”
He said Infrastructure Minister Nichola Mallon had asked for a second opinion “on the quality of the inspections that have taken place” and that the DVA was exploring all options, including how quickly new lifts could be purchased.
In a statement, Mr Duffy added: “The DVA recognises the considerable inconvenience and disruption this will cause for many people and sincerely apologises that it has been unable to rectify this situation more quickly.
“Given the urgency of this situation, we are asking the public to follow media, social media channels and nidirect for updates.
“Staff will also be kept fully informed by their centre managers.”
About 5,000 MoT tests had already been cancelled after the cracks in lifts were detected.
Drivers affected by disruption at vehicle test centres were told on Saturday they would be granted temporary MoT exemptions from Monday.
However these cannot be issued for four-year-old cars or taxis.
This is because four-year-old cars have never been through an MoT test before, meaning they do not have a certificate to extend, while taxis are covered by different legislation.
The DVA previously said these vehicles would be prioritised and Mr Duffy said on Monday that their tests would be carried out in the lanes normally only used to for lorries and buses – which remain open.
Unlike in the rest of the UK, MoT tests in Northern Ireland must be carried out at 15 government-run centres.
In an internal letter sent to its staff last week the DVA revealed the lift inspection results.
It said signs of cracking were first discovered during an inspection of Larne MoT centre in November 2019.
The letter added the safety of staff and customers “is of the utmost importance” and lift repairs have already begun.