The NZTA and the Government want Uber brought in line with industry regulations. The Government announced sweeping legislation changes on April 21 - safety reforms proposing ride-sharing operators like Uber should be subject to the same regulations as taxis.
However, the NZTA is not waiting for the law to change.
"A number of drivers operating under the Uber brand are committing offences. The most common offences are against the law requiring all passenger services to be operated under a transport service licence ... to have a passenger endorsement on their driver's licence ... and the requirement of vehicles to have a certificate of fitness, which is a higher standard of certification than a warrant of fitness," an NZTA spokesman said.
The NZTA has banned staff from using Uber on work time and urged caution over personal use as well, due to drivers operating without meeting the requirements of the taxi industry.
Potential medical conditions are one of the reasons why and the NZTA says it is keeping a close eye on drivers.
"The Transport Agency is aware of two Uber drivers who are medically unfit to drive a vehicle in a passenger service, both of whom have been served with prohibition notices," an NZTA spokesman said.
"The Transport Agency uses a range of techniques to monitor compliance with the laws it administers including audits, investigations as well as complaints and other information it receives."
The Herald approached Uber for comment on the two drivers with serious medical conditions, drivers being taken to court and response to other NZTA action.
In a blanket statement, Uber said safety was important.
"The safety of our riders and driver-partners is a top priority," a spokesman said.
"Our safe, fast and affordable screening process enables more Kiwis to access economic opportunities provided by ridesharing, while delivering the safety outcomes the travelling public want and expect.
"We welcome the Government's recent commitment to reduce compliance costs and simplify requirements for small passenger services in New Zealand, and look forward to working through the details in the coming weeks and months."
The spokesman said there was no progress on its hunt for a lobbyist to take on the new job of head of government relations. The right candidate must be a "strong campaigner".
With the Government proposing sweeping changes to the taxi industry - forcing ride-sharing services like Uber to start operating under the same regulation as licensed taxis - Uber wants someone experienced in influence as it braces for pivotal law reform.