There are calls for the wearing of face coverings to be made mandatory in taxis.
Some drivers say passengers are refusing to wear them, while others have reported customers coughing and spitting inside their cars.
Since July it has been compulsory to wear a face-covering on public transport such as trains, buses and trams.
However, the legal requirement has not been fully extended out to the taxi sector.
General Manager of Free Now Niall Carson says it has led to confrontation between drivers and customers.
He said: "Taxis are playing a really important role in bringing people to work and certainly, this is just an oversight, I would see, that the government haven't legislated for it properly.
"Drivers still lack this clarity, we don't see it being made mandatory.
"If you go into a shop, if you use public transport, you must wear a mask but the 14,000 drivers working with Free Now are in a difficult position where they are unable to demand or request that passengers wear face masks by law.
"It's a really difficult position for drivers.
"The drivers I know are good family people who never want to see a passenger stranded.
"But when they arrive and the passenger or passengers refuse to wear a face mask, it's a really difficult position and one that's resulted in standoffs and it's an unfortunate and uncomfortable position that drivers shouldn't be placed in.
The taxi company is calling on the government to address the matter to improve the health and safety for everyone involved.
Taxi drivers are reporting that there has been around an 80% drop in business due to COVID-19 restrictions and many are left waiting hours for a job.
Reporting by Josh Crosbie