Shocking figures from the Motor Trade Association over warrants of fitness.

End of year WOF figures show four in every 10 vehicles aren't roadworthy enough to pass their first inspection.

More than 1.8 million vehicles failed their first warrant of fitness inspection last year.

MTA Advocacy and Strategy Manager Greig Epps says the 41 percent fail rate should ring alarm bells for all road users.

He told Mike Hosking people need to stop relying on their warrant to alert them to issues with their vehicles.

"We're really concerned that people are just forgetting about the maintenance on their cars."

He says they need to be able to look better at the data they already have.

"A lot of this has to do with NZTA systems. We know that lights compromise 26 per cent of the fail rate, but that could be an indicator, it could be a licence plate light."

Epps says if you can't maintain your car yourself, take it to a professional.