Used car dealers say some customers expecting a clean car rebate are getting hit with a fee instead because official data is changing even as the vehicle is being sold.
The Clean Car Discount scheme is having to alter wrong or missing emissions or safety-rating data as it goes along.
Christchurch car dealer Peter Cullen has a dozen virtually identical Mazdas Azelas on his lot at Value Cars Warehouse, which he had marked up as having rebates.
But last week, when he went to print out a window sticker for the latest Azela, the official Rightcar site produced something else. "It's actually a fee now, it's changed midstream.
"Then I've subsequently gone and checked all the previous models. We've already marked them up as rebates, which they were, and now it appears they're all fees."
The fee is $470 and the rebate is about $500.
Because Cullen is convinced the new data is wrong and the cars should get a rebate, he is reluctant to change the window stickers - even though that might force him to pay the difference for the customer.
"I know it's not a fee car. But how do we prove that? I don't know. The public will blame us, not the government."
He also had cars with chassis numbers one car apart, where one had no fee, and the other a fee.
The agency's response was "fluffy", simply saying the data had changed, he said.
"The government is forcing us to mislead the public," he said.
Several other dealers said they had problems with a popular Honda hatchback where the safety rating was shifting: some at three stars got a rebate, others at two stars did not, they said.
Documents released under the OIA show transport authorities knew they had poor data for determining a rebate or a fee heading into the scheme's launch in April.
A Ministry of Transport report about CO2 emissions data for used cars, the way emissions are tested, and fuel consumption says: "Nothing reliable for used vehicles until June 2019 - high non-compliance since then as well."
NZTA Waka Kotahi said it ran regular updates from January to April to clean up this data, and that has carried on since.
Internal emails released in 30 files under the Official Information Act say the agency is dealing with "incorrect" motor vehicle registration data that requires a "workaround".
These show major Japanese car importer Nichibo called the system "a minefield".
"Work continues to correct, with a cycle of 2-3 data updates each week, to continually improve the underlying data," Waka Kotahi's programme director emailed on April 8, seven days after launch.
During just one such update, on April 6, the records for more 298 vehicles were fixed and 830 were rejected.
Waka Kotahi insisted the responsibility for providing accurate data sits with the vehicle importer.
Its service was "not the only, or even the preferred data source", it said. Waka Kotahi and the Ministry of Transport had worked since 2019 to improve the rules on data, it said.
The OIA emails show about 30 dealers asking the agency to urgently fix data in the week after the launch.
"Errors are now being shown on Toyota NZ and store advertising, misleading the public and creating reputational risk," Toyota NZ said on April 8.
Toyota told RNZ last week "there are no lingering data problems". Several other dealers agreed but others said problems persisted, with one saying hybrids and plug-in hybrids were the worst. Some are paying $300 per car to get guaranteed emissions data on European used imports.
The emails show Waka Kotahi was keen in April to tell the media the problems were minor, bedding-in ones, even though it was not sure about the scale of them. "We are still having difficulty getting figures we are confident about," a communications staffer said on April 8 while preparing a report back to the Transport Minister, following media queries.
After RNZ reported the industry was saying thousands of cars could be affected, the communications team said: "If we can convincingly pour cold water on that, it would be good."
Around the same time, a senior manager said "the information required is hard to come by". Another said that overall there was a "very low number" of problems, but added: "Given we have more cases than we are expecting, there is a spike, and we are working through each one as quickly as possible."
The Ministry of Transport asked Waka Kotahi about a gap where "hundreds of models" of a late-model Japanese used imports appeared to lack the right identifiers.
"Without these being loaded in, it means that the wrong CO2 value will be assigned on many used imports where manufactured from 2018, and probably all used imports manufactured from early 2021," the ministry official said. "It may also reduce consumers' ability to discover the full set of low emission car options."
The agency's top adviser on clean cars Iain McGlinchy responded: "It's difficult to work out from the emails what scale of the problem is. There seem to be more questions than answers at present."
He also urged his team to fix a separate problem, the scheme was putting a full fee on cars that lacked emissions data. "It is important to find out why the system seems to be skipping the other steps," McGlinchy said on April 7.
On April 27, the agency told RNZ there were no "system issues" and that a total of 145 vehicles had had their emissions data queried
The OIA emails contain an estimated 5 per cent of used cars were affected, and speak of the team being "donkey deep fixing the issue".
Waka Kotahi in a statement said was car dealers' responsibility to review emissions data by querying it with the certifier of a vehicle when it is imported or generating a label in Fuelsaver.
The agency was following the guidelines for when CO2 data was lacking, which could be because certifiers had keyed it in wrongly or the vehicle was not yet certified.
Dealers had to be as specific as possible to find the right data on Rightcar, such as using a chassis number.
The agency did not comment on how good its own data is now and did not say if it had addressed the problem of its system "skipping" steps and defaulting to a full fee when there was no data about a car.