Auckland Council is charging customers three full days' parking fees if they lose their ticket at three of its central city carparks.
At the Civic, Victoria St and Downtown sites parkers are being stung $72 for a "lost-ticket fee" even if they have only parked there for a few hours.
Other Auckland carparks operated by private firms such as Wilson, Tournament and SkyCity charge customers the equivalent of a day's casual parking if they can't find their ticket - ranging from $28 to $75.
Watchdogs the AA and Consumer NZ have slammed the lost-ticket penalties as "excessive".
"These charges could potentially be challenged under the Fair Trading Act, if considered to be unreasonable," Jessica Wilson, head of research at Consumer NZ, said. "The fees do appear to be steep and unfair."
It normally costs a maximum of $24 a day to park at the Auckland Council sites.
Charging people who have lost their tickets three times the maximum daily amount - no matter how long they have parked there for - is "unjustifiable", Mark Stockdale, senior policy analyst at the AA, said.
"These paper tickets are not difficult to lose and I am concerned people are being unfairly penalised at council and private carparks for making a simple mistake," he said.
"Charging people for a full day's parking for losing a ticket is bad enough but to be stung for three times that amount is excessive.
"There is technology available, including apps and number plate recognition devices, which can tell when a vehicle entered a carpark, so if you lose your ticket you should only be charged for the time you were actually there.
"I suspect this technology has not been introduced as these lost-ticket fees must be a lucrative revenue stream for the carpark operators."
Auckland Transport media relations manager Mark Hannan said there was generally one lost ticket for every thousand transactions.
He said the lost ticket fee was based on parking for three days at the maximum daily rate and "serves as a deterrent to avoid customers deliberately throwing away tickets and claiming they had parked for less time".
"There was an issue with customers leaving their cars in buildings for several days while they went to the Gulf Islands and claiming their ticket had been lost. The charging of a lost-ticket fee is a standard industry practice.
"Discretion may be applied by staff in some limited circumstances but Auckland Transport generally has the lowest daily parking rates in Auckland and we consider our rates are good value."
Hannan said the council was scoping new technology which could do away with tickets by automatically calculating parking fees and charging to an app. "But that technology is still being refined," he said.
Wilson Parking has 140 sites in Auckland and charges a lost-ticket fee at its 11 barrier-operated facilities.
These charges range from $30 at Carlaw Park to $75 at main carparks such as Elliott St and the Pullman Hotel.
"The fees vary based on the carpark's rates and the number of parkers who generally stay longer than one day," Laura Burns, spokeswoman for Wilson Parking, said.
Tournament Parking charges a full-day casual parking rate of $28 at its busy site at Newmarket mall for lost tickets. Auckland Airport charges $40, also the equivalent of a day's parking there.
"We have video cameras in operation and, when we can, we will try to work with customers to resolve lost ticket issues to their satisfaction and in a way that is fair," a spokeswoman for Auckland Airport parking services said.