People with cars affected by a compulsory airbag recall might miss out on a WoF, if they don't the work done.

Tens of thousands of drivers ignored the initial recall notice for cars with Takata Alpha airbags.

The bags are known to explode, and can fling shrapnel at the driver.

Consumer Affairs Minister Kris Faafoi says it's possible people will find they can't get a Warrant of Fitness if a replacement bag isn't fitted.

"A threat of that might get us a little bit more momentum towards the end of the period, but I don't think we need to do that yet, certainly for the first six months."

It follows the hard line the Government has taken in pushing back against the faulty bags.

It's declined a request from the Vehicle Importers Association to delay the start of the recall, as they wanted to bring in a shipment of cars, some of which are known to have the faulty bags.

Faafoi says concerns for public safety overrode their request.

"So as of now, no cars with the faulty airbags which we are targeting will be allowed to be imported to the country."

The recall deadline is the end of 2019.