The latest mistake is being attributed to a mailout contractor, but Auckland Transport is taking responsibility.
Parking and enforcement manager Trevor Starr told the Herald last night Auckland Transport was unaware of the error when it happened.
"As a result, 237 outstanding fines were lodged with Baycorp.
"When the problem was identified on January 30, Auckland Transport sent apology letters to the 237 customers affected."
Mr Starr said Baycorp had been instructed to delay collections for 35 days, to give motorists a chance to pay up "in the normal way".
"After the 35-day period, if payment or contact has not been received, Baycorp will continue to pursue collection as normal."
Debts from outstanding fines would not be listed in the meantime on anyone's credit history, and Auckland Transport had taken steps to guard against any recurrence of the problem.
"We sincerely apologise for the error," Mr Starr said.
The problem was raised with the Herald by a motorist who said he had paid a $12 park fine before receiving a demand letter from Baycorp.
The apology letters sent to all those affected by infringement review manager Liz Hogan, said the notices they had received were issued correctly despite what happened subsequently.
"If you have paid this infringement notice at Baycorp, your payment will be allocated against the notice and no further action taken," she wrote.
Auckland Transport contracted Baycorp in 2012 to chase motorists for parking and other vehicle fines, and in the first three months the collector saved its client $400,000 in court costs by persuading greater numbers to pay up in time.
The transport body's chief operating officer, Greg Edmonds, said at the time that payments had risen from about 4300 a week, to 6300 simply through use of the words "debt collection agency" on letters sent to motorists.
Auckland Transport When the wheels come off....
Last week
*Commuter Marius Botha pays $190 for a monthly pass on his Hop card, and is told the next day it is $10 in deficit and he has to top it up. His card starts working again after he goes public with his case.
Last month
*Car-pooler Simon Soulsby has to get witness statements from two passengers to escape $300 in fines imposed for being in the Onewa Rd T3 high-occupancy lane, after an earlier appeal failed.
*Graham Hughes is let off a fine for using the same lane only after the AA intervened on his behalf.
*Three mothers of children too small to show up on video of cars in the Constellation Drive T2 lanes have to gather statements from schools and sports clubs before being let off with warnings.
December
*Auckland Transport admits it has "technical problems" with charging on Link buses.
