The NZ Transport Agency has begun contacting about 10,000 Kiwis, whose cars may not have been properly checked during their regular Warrant of Fitness inspection.
Law firm Meredith Connell is reviewing the cases involving cars that may not have been checked properly and managing partner Steve Haszard says owners will be able to have their vehicles "re-checked free of charge via a Transport Agency voucher".
He said Meredith Connell had completed a review examining the "most urgent" cases.
"Significant progress has been made and reviews completed of the most urgent files where public safety was potentially at risk," he said.
"We have provided recommendations to the Transport Agency. On the basis of these recommendations and following legal processes the Transport Agency is stepping up enforcement action for non-compliance across all regulatory areas for which it has responsibility."
While the public should notice increased action from the Transport Agency in the coming weeks, the process would still take time because it was "legally bound to follow due process".
"For example, in some complex cases further investigation is required to meet evidentiary requirements or there are legal processes underway which need to run their course," Mr Haszard said.
The news thousands of Kiwis may have been issued Warrants of Fitness without having their cars properly checked has led to strong criticism of the NZTA and its ability to oversee the vehicle safety checks.
Car passenger William Ball died in January after a frayed seatbelt failed in a vehicle given a Warrant of Fitness by a Dargaville company.
The NZTA admitted knowing since 2011 that Dargaville Diesel Specialists was failing to carry out critical WOF checks but, in line with its approach at the time, was more educator than enforcer.
The owners of nearly 2000 vehicles that received warrants from the company were given offers to have them rechecked.
Transport Minister Phil Twyford announced in October that Law firm Meredith Connell had been brought in by the NZTA board to review 850 open compliance files and taken over its compliance function because it had failed to carry out its regulatory responsibilities to the standard he expected.
"I have formally instructed the Ministry of Transport to review NZTA's regulatory performance," he said at the time.
"There are a number of issues that need to be addressed to provide assurance to me, and the public that deficiencies around NZTA's regulatory performance are identified and addressed, and that is why we are asking for advice on what changes to the regulatory function are required."
The review is due to be completed by the end of March next year.