The number of cars failing their Warrant of Fitness is rising to worrying levels.

This year, 41 percent of cars failed their warrant, which accounts for more than a quarter million vehicles.

The number has been rising since car owners have to go for the warrant  every year instead of every six months.

Greig Epps from the Motor Trade Association told Heather du Plessis-Allan that it is worrying, but they are not sure if it is the fleet is more unsafe or people aren't looking after their cars. 

"We're getting reports from our members of tyres and brakes coming in that are very, very worn out." 

However, Epps says the number of cars failing the first time is going up, the reasons why are staying the same.  

He says the worry is that people were too reliant on the six monthly checkup to know what was happening to their car. 

"We just want people to be more mindful of their vehicle."

He wants the NZTA to look into this and work out what the cause may be.