A coffin on wheels is how police and vehicle inspectors described one car ordered off the road during a weekend blitz on boy racers in Tauranga and Mt Maunganui.

Dozens of "death traps" modified by backyard mechanics were stopped by authorities, declared unsafe and sidelined.

The combination of inexperienced drivers and unsafe cars had Western Bay police predicting it was only a matter of time before the vehicles caused serious accidents or deaths.

Of the cars inspected over Friday and Saturday night, 29 were "pink stickered" and were not allowed to be driven again until they had been repaired and passed an inspection.

Police gave 27 warnings, dished out 128 fines, and issued eight tickets for traffic offences that will require a court appearance.

The worst car stopped during Operation Compliance was seen bumping its way along Hewletts Rd at 11.43pm on Friday.

Senior Constable and crash analyst Chris Hills, who has 15 years' experience in the police, said the car was a lethal weapon.

The unwarranted 24-year-old Toyota Corolla, which was incorrectly registered, was directed to On Road New Zealand where it was examined by inspectors.

Once stationary a smell of burning rubber emanated from the car.

On closer inspection it was not hard to work out why.

The body of the car sat on top of the tyres. There were no springs suspending the vehicle above the wheels.

Turning the car was almost impossible as the tyres rubbed against the guards - the front left tyre had broken through, exposing a dangerous jagged metal edge.

"This could kill someone," Mr Hills told the male driver.

"It's an accident waiting to happen.

"It's a foolish thing to do to come out on the road with a vehicle like this."

Four others in the car stepped out from the lime-green death machine.

The driver, 16-year-old Rhys Fleming, revealed he had already popped a rear tyre earlier in the night.

He was not perturbed by the officer's news.

"More people die in normal cars than these," he said.

"I know it's a bit dangerous but I don't go on the motorways."

But the On Road inspectors confirmed how dangerous the car was.

"It scares me to think that I am on the same road as these death traps," Mr Howard Cocker said.

"By getting this off the road we have potentially saved someone's life. It's the equivalent of a coffin on wheels."

For his efforts, the young driver received $1000 in fines - $600 for operating a dangerous vehicle, $200 for an expired Warrant of Fitness and $200 for incorrect registration.

Boy racers are going to great lengths to make their cars stand out by making modifications that could have fatal consequences.

Instead of taking their cars to mechanics they are doing the work themselves.

The most common modifications included cutting suspension springs to lower the vehicle, altering the exhaust to make it louder, fattening the tyres, tinting windows and plastering stickers across rear windows.

Operation head Sergeant Lester Polglase, who has 30 years' policing experience, was shocked by the number of dangerously modified cars on the road.

"It's about their safety and other road users. It's not about tickets," he said.

"We're hoping the cars that come here pass.

"If they don't, they are unsafe and need to be brought up to roadworthy standard. It's disappointing these modified cars were not done properly.

"The kids are risking their lives and everyone else's."

Many of the cars stopped were not warranted or registered.

Some were registered for the wrong class - one being registered as a tractor rather than a car.

Legal changes

* Guidelines for light vehicle modifications can be found on the Land Transport New Zealand website using the link below.