Wheel-clampers have been accused of intimidation and abuse - and the Government has admitted too little has been done to pull the industry into line.
Yesterday more than 30 people contacted the Herald to allege unfair treatment by clamping companies - in one case an agent sneaked up behind a car with its engine still running and occupants inside to clamp the rear wheel.
And police have become involved in heated disputes.
The response came after yesterday's front-page article on Glen Vickery, who was awarded $550 after a disputes tribunal ruled NZ Wheel Clamping's warning signs were unclear.
But a traffic lawyer, the AA and Consumer NZ say people do not have the time or money to pursue a disputes tribunal claim, and outcomes remain uncertain.
Yesterday the newly appointed Minister of Consumer Affairs, Simon Bridges, told the Herald he had sought advice on how to address a "subject of growing concern".
"There is no legislation regulating wheel-clamping on private property. And the applicable law is based around common law principles.
"I accept the application of those is often unclear and inconsistent. You are getting situations where what happens in one disputes tribunal in one area is not necessarily what happens in another."
Mr Bridges said his starting point was that the industry should be encouraged to self-regulate - this was despite then opposition transport spokesman Maurice Williamson promising in 2008 that National would regulate the industry.
"I've seen what a pack of cowboys are out there, actually tearing good members of the public to shreds," Mr Williamson told the Fair Go programme at the time.
"We will actually do something to bring these guys into line and regulate them."
Mr Bridges acknowledged not enough had been done by the Government to tackle the problem.
"In the first instance I want to get some advice. But ultimately the Government does have the option of stepping in and regulating. That's not an idle threat."
Manurewa Local Board deputy chairwoman and town centre manager Angela Dalton has met NZ Wheel Clamping as well as local police after receiving numerous complaints about clamping in the area.
While police were often called when clamping incidents threatened to boil over, their position was that such disputes were a civil matter, she said.
"There was a lady whose car was clamped, there was a verbal altercation, she bent down to remove the clamp, and the clamper did push her and he was arrested for assault."
Ms Dalton said one local man had become so enraged after witnessing a clamper sneak up to clamp a car while it was still running that he took matters into his own hands.
The 63-year-old stood outside the entrance to Southmall carpark warning motorists they risked being clamped - leading to a shouting match with the clamper working the area.
But Sean Hika, group manager at NZ Wheel Clamping, said no agents had been arrested while on duty.
The company did not condone abusive behaviour by agents under any circumstances - despite its agents copping worse themselves, he said.
"We've had people chase our guys with hammers, with wheelbraces."
Traffic lawyer Steve Cullen said landowners can claim parkers accept the risk of being clamped but discretion was needed in more complicated cases such as Mr Vickery's.