The cases included worn brake pads, damaged headlight adjusters and rusted rotors being put into imported cars.
Associate Transport Minister Simon Bridges told the Herald that he had asked the Ministry of Transport to find a way to stamp out the practice.
"I remain concerned about any practice that could jeopardise our vehicle compliance systems or the safety of vehicles on our roads."
NZTA spokesman Andy Knackstedt said the scam's scope was limited to a small number of importers.
Parts-swapping was unlikely to be done by large-scale importers who sell vehicles to dealers, he said.
"It is more likely done by smaller dealers who directly import a few vehicles so that it is more important to maximise the profit of every vehicle."
Last year about 75,000 used vehicles were imported. Each must have a safety and quality check, and often worn or damaged parts will have to be replaced before the car is rechecked and allowed to be sold.
The scam has seen some dealers put the old parts back into vehicles after the recheck has been done and compliance granted.
If a vehicle is certified it is issued with an entry warrant of fitness, which needs to be replaced if it is more than one month old at the time of purchase.
Mr Knackstedt said that while dealers taking part in the scam may be in breach of industry standards or consumer law, it was unlikely any transport legislation had been breached.
"The NZTA's options are limited in terms of addressing the issue through transport rules or regulations."
Mr Bridges said the Ministry of Transport would work with industry organisations such as the Motor Trade Association to address the problem.
"I would reiterate NZTA's message to anyone purchasing a used imported vehicle to have an independent pre-purchase inspection carried out."
