Clampers are lying in wait to pounce on motorists parking in the wrong spot within seconds, demanding "disproportionate" fees to free driver's wheels.
Some clampers are not signed up to a voluntary code of conduct drawn up by the Automobile Association which allows a 10-minute grace period for drivers before their cars are targeted.
In a Herald investigation, a parking enforcer for Amalgamated Car Parking Services was seen sitting for hours in an unmarked car on Auckland's Dominion Rd on three evenings during two weeks waiting for unsuspecting motorists to park where they shouldn't.
At least eight cars were clamped at the set of privately-owned car parks next to the Countdown supermarket.
Drivers were forced to pay $150 on-the-spot fines to have their vehicle released.
In one case caught on video by the Herald, a driver parks in the spot to pick up takeaways. Our timer shows that at the one minute, 40 second-mark (or 100 seconds), the parking enforcer exits his own car.
He clamps the man's car, returns to his own car and is approached by the driver who pays to have the clamp released. The whole process takes less than five minutes.
In another case, a woman broke down in tears and others tried to protest in vain, with the clamper instead threatening to tow their car at nearly double the cost if the fee wasn't paid immediately.
The landlord for 126 Valley Rd is Eddie Li, who said he had arranged for the car parks to be managed on behalf of the businesses which leased his land.
Amalgamated boss Craig Burrows said wheel clamping was the only way to make sure people paid if they broke the rules.
"If people have parked in a space where they're not supposed to then you know, like anything there's going to be enforcement made," he said.
He did not trust that people would pay if his company issued breach notices, meaning the parking company would have to spend time and money chasing them up.
Wheel clamping was a legitimate way to enforce parking rules and the only way to make sure people coughed up because tickets would be ignored, Burrows said.
"We're always the baddies. At the end of the day, the person's breaking the rules."
Amalgamated has not signed up to the industry code of practice, which has been signed by three companies.
A Countdown spokesman told the Herald the reserved section of the car park was not owned with the supermarket, it just happened to share the same space.
Consumer NZ labelled the practice "pure revenue collecting".
"The model is based on catching people, not providing parking," said chief executive Sue Chetwin.
"Once you've been clamped, you're in a completely vulnerable situation because you've got to get your car back somehow," Chetwin said.
"You have to pay the fees and argue later."
Automobile Association spokesman Mark Stockdale said that while it was a driver's responsibility to check for signs they were not parking where they shouldn't, wheel clamping was out of proportion.
"'Even if you did ignore the rules, clamping for parking for five minutes is disproportionate, even if you're in the wrong."
Enforcement companies should issue much cheaper breach notice.
In 2015 the code of practice for parking enforcement on private land was drawn up by stakeholders in the parking enforcement industry, including the AA, Consumer NZ and representatives from the industry.
At the time, it was reported the code would help the industry self-regulate and all but eliminate the practice.
As well as the 10-minute grace period, the code states clamping should only be used as a last resort and staff must not use threatening language or behaviour.
Wheel clamping is not illegal on private property in New Zealand, however, the code said breach notices should be issued in the first instance.
Towing should only be used if the car was taking up reserved space or creating a hazard.
Clamping was deemed appropriate only when towing was not a practical option.
Stockdale said if all parking enforcers followed the rules of the code clamping wouldn't be an issue.
When asked why he thought some companies hadn't signed the code, Stockdale said it was possible some didn't know about it, but conceded for others clamping was their bread and butter.
"For some parking enforcement parking companies, the code is clearly going to be a challenge for them, because their business model revolves around clamping.
"Some will find it difficult to move their business away from clamping towards a breach notice enforcement model."
Parking enforcers' code of practice
If you think you've been clamped unfairly, check the key points of the code
1. Parking enforcers should allow a 10-minute grace period for drivers "in which to read terms and conditions signs and decide if they are going to stay or leave without having their vehicle issued with a parking breach notice".
2. There must be clear, easy-to-read and prominent signage which can be seen easily in the dark.
3. A wheel clamp or tow should not be applied when the driver is present or returns to the vehicle
4. All operational vehicles belonging to parking enforcers should be marked clearly with their livery or business name
5. Front line staff are required to wear a uniform and carry photo identification