The introduction of the Glider bus service has resulted in 85 west Belfast black taxi drivers losing their jobs, a spokesperson has said.
Brian Barr, transport manager for West Belfast Black Taxis, claimed some users of the rapid tranport system were not paying for tickets and therefore regarded it as a free service, which was affecting the black taxi industry.
Translink, however, said it has no significant concerns about fare evasion and ticket inspectors carry out spot inspections every day at different locations.
London-style black taxis have been operating in west Belfast for more than 50 years.
When the Glider service went into operation in September 2018, West Belfast Black Taxis said it employed 215 drivers, however now it has 130.
Speaking to the BBC, Brian Barr said: "Our main criticism of the Glider would be that due to fares not being taken on board the service. A lot of people feel: 'I'll take a chance. I'll get on it free'.
"If they see a ticket inspector they will then get off. If things persist the way they are going, eventually the Belfast black taxis service could ultimately fade away.
"That is our worry. It's a real big concern at the moment."
The Glider bus service went into operation in September 2018
Mr Barr said the Department for Infrastructure (DfI) agreed to allow black taxis to provide feeder services for those in housing estates on the outskirts of west Belfast to the main Glider route, however this deal was not followed through with.
"They assured us that we would be providing the feeder services, from Whiterock, Glen, and Shaws Road," he said.
"We should have been used. We are part of the public transport network. We have the same licences as Translink. So I don't understand [why] at the last minute, there was a U-turn done and we were not advised."
The DfI said talks had taken place, however they were not successful.
"The Belfast Rapid Transit team engaged with West Belfast Black Taxi representatives in relation to them having a role in feeder services," a spokesperson said.
"However these discussions were not successful and this option was not considered further in the design of the system."
Mr Barr also argued that Translink had an advantage over black taxis as they received a government subsidy.
The DfI provided £94.4m in funding to the Glider service: £48.7m on infrastructure improvements, £24.2m on buses and £7.4m on new ticketing arrangements.