NZTA is warning 10,000 drivers their warrant of fitness may be dodgy.

That's almost double the number already revealed, after warnings went out to 5500 vehicles from two suspended garages.

The new warnings include almost 3500 customers who got their warrants from Orient Motors in Glenfield, Auckland and 600 who got warrants from Te Aroha Automotive need to get them rechecked.

The agency "is stepping up enforcement action for non-compliance across all regulatory areas for which it has responsibility", said Meredith Connell's Steve Haszard who took over managing road safety compliance last month after the NZTA admitted failing to enforce the rules for years, and the government ordered a review into it.

Drivers can have their vehicles re-checked free of charge with a NZTA voucher.

The Transport Agency says action is taken against 74 vehicle testing businesses or inspectors, and vehicle operators, including 13 immediate suspensions.

This follows the law firm Meredith Connell today completing its review of 150 of the most urgent, open files at the Transport Agency.

Another 700 files are still being checked.

The public would notice further enforcement actions over the coming weeks, said NZTA.

Some of the names of those facing action have been withheld as legal action is underway.

One unnamed provider of driver licensing courses has had its right to do the work revoked.

It's the only immediate revocation amid an unprecedented wave of action by the agency.

"In some instances the risk to land transport safety or public safety is such that a company or individual is immediately suspended" without having to go through warning steps, the agency said in a statement.

Four transport services have also been immediately suspended, all of them unnamed heavy vehicle drivers.

"There is a very narrow ability to suspend a transport service licence holder. It can only occur if the transport service does not hold a certificate of knowledge, law and practise," the agency said.

Another 45 transport services and two service providers have been hit with a proposal to revoke their right to operate.

Nine warnings have also gone out - eight to transport services, which raised problems that now must be addressed.