The New Zealand Uber Drivers' Association says drivers are suffering a marked drop in income - but an increased workload - following a drop in the company's fare prices.
The app-based ride share service announced a 20 per cent drop in its prices, in April, which also coincided with a change in the process of becoming an Uber driver.
Whereas in the past someone hoping to be a driver would have to fork out $2000 and three months to finish various licence and medical checks, it now costs $20 and about six days to complete the full process.
The NZ Uber Drivers' Association chairman, Ben Wilson, acknowledged that the changes had brought on consequences to Uber drivers.
"Lots of the drivers were former taxi drivers who came to Uber because they thought it was a better service," Wilson told Fairfax.
"But with these price cuts, they are having to go back to traditional taxi driving."
It is thought a number of Uber drivers are now quitting the business, as they felt it no longer provided a sustainable income.
Uber had also removed rules requiring drivers to carry a passenger endorsement or passenger service licence.
That move is one worrying the NZ Transport Agency, which has called it illegal.
NZTA group manager for Access and Use, Celia Patrick, said: "Uber has stated that it is doing its own Ministry of Justice and driver licence checks before deciding if they will allow someone to drive for them.
"[But] these are far less rigorous than the mandatory background checks, medical checks and examination of a range of other risk factors which are carried out by the Transport Agency before we issue a passenger endorsement to allow drivers to carry passengers for hire or reward."
Patrick said the NZTA also required drivers to have a recent medical certificate and information about overseas criminal convictions as part of its passenger endorsement application process.
"We want to make sure that prospective Uber drivers are aware of these requirements and understand the possible consequences of driving without an appropriate licence or providing an unlicensed service - which can result in significant fines," she said.
"As a safety regulator we have no interest in standing in the way of innovation, but we have a responsibility to ensure that people carrying passengers for a living have been properly vetted and understand their responsibilities under the law."