"I remain concerned that there are potentially some practices which may not be in line with the Fair Trading Act.
Meanwhile motorists are still getting stung with $150 fees for breaking the rules.
Finn Morrow was clamped outside the Chinese consulate in Ellerslie last Wednesday while getting a holiday visa.
Morrow had unknowingly parked in the wrong spot in a large parking complex for what he said was five minutes at most, and returned to find his car wheel clamped.
The union organiser said he was in and out of the consulate so quickly the clamper, who worked for Amalgamated Car Parking Services, must have seen him go in, knowing he was parked in the wrong place.
"What really annoyed me is that the guy would have seen me park there, seen me go into the consulate and not tell me that I'd be clamped.
"He didn't inform me when he could of that there was going to be the consequence, instead he let me go in and take the fine."
After paying a $150 on-the-spot fee Morrow had his wheel released.
There was signage and markings on the ground, but not near where Morrow had parked.
For many of the parking spaces in the complex it was unclear who was permitted to park in them because the paint on the ground saying who was allowed had faded, or been painted over - sometimes more than once.
Morrow said he was concerned Amalgamated had a vested interest in not making it clear where people could park, in order to collect revenue.
He thought a ten-minute grace period, as followed by parking enforcement companies signed up to a voluntary code of practice, should be mandatory.
However Amalgamated boss Craig Burrows was not having any truck with the idea of a grace period.
"Give me one reason why people should park on someone else's property for free," he said.
"Why should they park where it says they're not supposed to. Why do they think it's okay to park somewhere for one minute or five or ten minutes."
