"We can confirm that there have been some intermittent performance issues today with the system that NZ Post use to process vehicle licensing ... transactions. We're working on resolving the issue as a matter of urgency."
The spokesman said motorists unable to renew at a NZ Post store have the option of renewing online at www.nzta.govt.nz/renew.
Problems with the system have so far been restricted to ACC, which bungled the cuts to at least 9000 motorists' car registrations.
The chaos caused by the new car registration system has led to it being labeled the "Novapay of transport" by Labour.
The party's ACC spokeswoman Sue Moroney said minister Nikki Kaye needed to scrap the entire system after errors emerged in the lead up to its launch today.
The new system links each car model and make to a "risk rating" then adds a fee to the cost of car registration that is between $68.46 for the safest vehicles and $158.46 for lower ranked models. Previously, all motorists paid $198.65.
The system has caused frustration with motorists after computer errors impacting about 9000 motorists. In some cars, the computer system designed to the run the rating system put cars in the wrong risk rating band, charging drivers too much money. Other motorists had the computer mis-read their model of car and charge a higher rate.
The individual ranking of each make and model fluctuates against a database of accident data at Monash University, an Australasian safety ranking system based on laboratory tests and information from the insurance industry.
But even those unaffected by the computer errors found frustration in a risk rating system which listed cars they assumed to be safe as dangerous and worthy of higher costs.
"The whole system is so complicated. I confidently predict there will be issue after issue. She needs to scrap the system. It will not deliver the outcomes she thinks it will. She has been sold a lemon."
The idea of linking the cost of registration to risk rating was hoped to encourage motorists towards safer cars - a premise Ms Moroney said was flawed.
"It's not a perfect science. The minister has implemented a system that pretends it is a perfect science and it will change behaviour."
The first day of ACC's new system for calculating levies was hit by the revelation the system had multiple errors. The corporation admitted yesterday 9000 people had been charged the wrong amount for car registration and the number was expected to grow until the problem was fixed.
The biggest fault was one which ACC discovered at least six months ago and, despite attempts, had failed to fix.
ACC's Sid Miller told the Herald he hoped the problem would be fixed by next week and that increasing numbers of motorists would be wrongly charged until then.
The new, cheaper car registration costs are the most public show of progressive $2 billion cuts to ACC levies since 2012.
Mr Miller said motorists should still pay for car registrations even though some of those who did would pay the wrong amount.
All those who had paid too much would be tracked down and given a refund.
"I apologise for the inconvenience this has caused but we will be proactive in making sure they are refunded."
He said the number of people affected would continue to grow until the identified errors had been fixed. The error with wrong safety bands would not be fixed until next week, while the issue affecting fewer people was hoped to be solved overnight.
"This is the key thing in getting the fixes in place. Until we get the fixes in place then that number does grow. That's why we're working with full priority to get these problems resolved."
