The chief executive of the troubled Driver and Vehicle Agency (DVA) is set to be grilled by MLAs on Wednesday as the chaos around MoT tests in Northern Ireland continues.
All MoT testing for cars and light vehicles were suspended last Monday due to safety concerns over cracks in vehicle inspection lifts.
The DVA warned that replacing the scissor lifts at the 15 MoT centres could cost millions of pounds and take months.
Paul Duffy is set to appear before the Department for Infrastructure (DfI) committee on Wednesday to demonstrate how the DVA is attempting to resolve the issue.
Infrastructure Minister Nichola Mallon, who has already commissioned two separate reviews into the crisis, will also provide an update.
DUP MLA Keith Buchanan, who will be sitting on the committee, raised a number of concerns last night and said the "key question" is whether MoT tests will return at all in 2020.
"In particular, we need to provide certainty for the thousands of people whose MoT tests have already been cancelled, or who have an upcoming test and are uncertain as to whether it is going ahead," he said.
"I trust that the Minister will demand that the DVA fully explain the procurement details behind the contract with the manufacturer who installed the vehicle lifts in 2011/12 and subsequently discovered the cracks in a sizeable 48 out of 55 lifts.
"The focus must be the number of cycles which a vehicle lift can perform annually.
"What did the manufacturer suggest the life span was? We need to find out what figure is covered by the agreement and how long these machines should have been fully operational for."
Mr Buchanan added that the life span of the lifts must have been discussed during the procurement process and called on the publication of the procurement documents.
He said the DVA must explain what plans were in place for new lifts and asked how that decision was made.
"From one visit to one MoT centre, I was told the lifts in that centre operated at an average rate of 90 cycles - one lift up and down - per day for 320 days per year and were operating since 2011/12," he continued.
"On average that would suggest these lifts would have 28,800 cycles per year and since 2012 they would complete 230,400 cycles.
"I am aware that in the National Car Testing centres in the Republic of Ireland, use of vehicle lifts provided by the same manufacturer has also been suspended.
"I am concerned that this could exacerbate the delay in supplying working lifts to MoT centres here in Northern Ireland and trust that the DVA can set out steps it would take to mitigate such an impact.
"I look forward to receiving full and satisfactory answers to these questions, in the knowledge that this is causing considerable ongoing inconvenience and uncertainty for a vast number of drivers."
The DfI was not available for comment on Tuesday night.
Meanwhile, Inspector Rosie Leech from the PSNI Road Policing Unit said that where police detect a vehicle without a valid MoT certificate, and providing the vehicle appears to be in a roadworthy condition, officers will be encouraged to exercise discretion.
"Priority is being given to those with MoTs that have expired or expire today, so motorists can proceed to tax their vehicles," she said.
"Driving without vehicle tax is not prosecuted by PSNI and falls within the remit of the Driver and Vehicle Licensing Agency [DVLA].
"Where a police officer encounters a vehicle without tax and it is outside of the 14-day grace period provided for in the legislation, a referral is made to the DVLA.
"It is for DVLA to determine whether they will take action in such cases.
"This is a fluid situation but I want to reassure the public that we'll keep in touch with our partners in DVA and if there's any change that affects our stated position, we will advise you as soon as possible."
The DVA asked the DVLA last week not to sanction Northern Ireland motorists affected by the MoT crisis. It came following calls for clarity around the issue of untaxed vehicles being clamped in Northern Ireland due to the debacle. Exemptions have been issued to drivers whose tests have been affected; however this does not apply to cars that are four years old or taxis.
In order to tax a vehicle, a valid MoT certificate is needed. There have been concerns raised that owners of cars not covered by the exemptions are having their cars clamped through no fault of their own because their test was cancelled.