A row has erupted over whether taxis should be allowed to use Belfast's city centre bus lanes on a permanent basis.
Allowing cabs into bus lanes will put bike riders in danger, a cycling organisation has warned.
But a Belfast taxi firm boss said the "antagonistic attitude" of some was the real issue.
As part of a 12-week trial staring on Monday, 4,000 more cabs will be able to use the restricted lanes.
Buses, motorbikes cyclists and certain types of taxis are already able to use them.
The trial will permit Class A taxis - the largest group of private hire cabs - into the restricted lanes.
However, Uber and other Class C taxis such as funeral and wedding cars will not be able to avail of the trial.
Fonacab boss William McCausland said some of his drivers had read comments online where cyclists said they would deliberately ride slowly and in the middle of the bus lane.
"All of our drivers are competent and able to negotiate around a cyclist with no issue," he said. "We recently sent a memo around our drivers to remind them to be mindful of cyclists - but sometimes the cyclists need to be more careful too; this aggression doesn't help anyone.
"At the moment our wheelchair accessible taxis can already use the bus lanes regardless of whether someone with a wheelchair is even in the taxi. It's ludicrous - nobody can justify it.
"You could get one of our Class B taxis drop you off to work one day and it could cost £4.80. The next day you could get a Class A taxi, but because it can't use the lane, you could be sitting in traffic and find the same journey will cost you £6.
"In the city centre lanes it will help our customers. If you're at the Europa and you've got a customer to pick up at City Hall it will make a big difference not sitting in traffic. To a customer, waiting every 20 seconds feels like 20 minutes."
A spokeswoman for cycling body Sustrans said it was concerned the 12-week trial would become permanent.
She added: "Cyclists are among the most vulnerable road users. We believe this trial contradicts the Government's own strategy to promote sustainable transport and active travel as it will hinder people to have the freedom and confidence to travel by bicycle for everyday journeys."