Transport Minister Phil Twyford says he is disappointed the New Zealand Transport Agency has failed to carry out its regulatory responsibilities to the standard he expects, but is pleased the Agency's Board has taken swift action to put things right.

The Transport Agency's Board has called in independent lawyers to conduct a review of 850 open compliance files. NZTA regulates all vehicles on the roads and licences people working in the transport sector.

Phil says he's asked the board to report to him regularly on progress and actions to address the compliance issues identified in the files.

The external independent review is being led by law firm Meredith Connell at the request of the NZTA Board.

It began in late September and based on preliminary findings, the Transport Agency is immediately strengthening its enforcement regime by increasing suspensions, with other legal actions expected to follow.

About 152 files require urgent legal or investigative review and that work is expected to be completed by early November.

Phil says NZTA was failing in its duty to properly check the companies that certify vehicles as safe for the road, and other services.

'When problems with these companies were identified, there was often no follow up. This is very disappointing. Public safety must be paramount.

'This failure, in my view, was in part a result of a reduced focus on the Agency's regulatory role over the last decade. Staff were redeployed and there was an emphasis on education rather than enforcement. This was exacerbated in 2014 when the Agency lost staff from its heavy vehicle compliance team."

Phil says the board had advised Meredith Connell will also lead the compliance function within NZTA. Where necessary, certifications will be revoked or other action taken on a case by case basis to ensure public safety.

'Where they are able to identify specific vehicles that we know are unlikely to comply with standards we will take urgent action to ensure they are inspected and if necessary re-certified.

'The board will look into how this went on for so many years and why it was not dealt with earlier. The Board has also advised me that the Transport Agency will be taking a more rigorous and pro-active approach to safety regulation from now on.

'Our Government is committed to saving lives on our roads. I want to assure the public that our roads are as safe today as they were yesterday, but not withstanding that, the Transport Agency is moving swiftly to ensure these lapses in the regulatory system are fixed as soon as practically possible."