Of the 24 complaints, six resulted in a licence being revoked – one for drink-driving, one for assault/unruly behaviour, three for driving behaviour, and one for a sexual complaint.
A second drink-driving incident occurred when the driver was not on duty, and "enforcement action" was taken.
In another case of sexual impropriety, the driver was suspended.
The total number of complaints received can't be released because minor complaints aren't recorded, NZTA says.
Queenstown Taxis boss Grant Scannell says new taxi permits being issued by the council next month will make drivers more accountable.
The council plans to initially issue 150 permits to vehicles operating from taxi ranks in Queenstown, at a proposed cost of $500 per permit.
Scannell says he fired a driver last year for essentially "kidnapping" a passenger – the driver locked her in the cab and drove to the police station when she refused to pay her fare.
When there's an issue with a driver, Scannell says he reports it to NZTA straight away.
He also claims a lull in business is driving bad behaviour outside of the cars.
He says his drivers have footage of independent taxi drivers pushing and shoving each other at the taxi rank, which he claims is because of fierce competition for fares.
"It's the quietest I've seen it for seven years," he says.
Bus and Coach Association's Anna Cleary says regulations are there to protect people from "unsavoury behaviour".
If drivers are behaving badly, "there's no place for them in the industry", she says.
