An increase in people flouting the lockdown travel restrictions has led to a spike in anti-social behaviour on west Belfast's Glider buses, it has been claimed.
A concerned driver has said he and his colleagues are prepared to go on strike unless Translink intervenes immediately.
The employees also want the company to reconsider stopping the Glider service from running until 10pm.
This follows attacks on drivers, intimidation and a rise in the number of staff suffering anxiety and panic attacks at the wheel.
In a letter sent to the Belfast Telegraph the driver, who asked to remain anonymous, told of the misuse of Gliders by youths and drug dealers.
He said the problem was worst in west Belfast, where there often are 30 or more passengers on board - twice as many as in the east of the city.
"During the last two weeks we drivers have seen a massive spike in the increase of traffic on the roads and people about the streets," the driver said in the letter.
"Because of this, the volume of passengers on board our vehicles has grown.
"Not only is it just passenger numbers that concern us, unfortunately there has been a grown increase of anti-social behaviour activity and the culture of teenagers hanging around at the back of the Glider causing trouble has now returned.
"We also are at risk with drug abusers on board now and have came under verbal abuse frequently from them and these teenagers."
The driver behind the letter said concerns had been raised with the Department for Infrastructure (DfI), including the proposition of running the Glider service from 7am to 7pm, and not until 10pm.
"Unfortunately the DfI that owns Glider has shot down any talks or previous attempts of the Glider service running onto 10pm. Before we had even tried for a 7-7 service," wrote the driver.
"The mental stress is bad enough but when late at night is when we as drivers are mostly exposed to these threatening and worrying situations we find ourselves in."
The letter author also highlighted other issues.
"We have had drivers threatened and tormented by gangs of youths," they wrote. "Drivers injured by broken glass caused from thrown projectiles, we even had a driver... have someone aim a weapon at them.
"We've had a number of drivers having both panic and anxiety attacks at the wheel because we simply do not have the means or help to deal with these situations."
The author said drivers had contacted Translink and their union Unite about the problems with anti-social behaviour on Gliders.
"We need help," the person wrote. "We as drivers feel it may be the final straw to take action and go on strike. Enough drivers are willing to do this if anti-social behaviour does not change on our transport."
Davy Thompson from Unite said attacks on bus drivers will not be tolerated.
"There is a clear process to be followed when these types of incidents happen and drivers should be aware of that process," he said.
"In the event of anti-social of a physical nature we have withdrawn services in the past and we would do so again in future if needs be."
A spokeswoman for Translink said no anti-social issues connected to the Gliders had been reported recently.
"We have received no recent reports of anti-social behaviour on our Glider services," she said.
"However, there has been a slight increase in youths gathering in contravention of current lockdown measures, which have been reported to the PSNI.
"These are very challenging times; our staff are working extremely hard to ensure we continue to deliver vital public transport services for key workers and those making essential journeys. We would encourage and remind all customers in line with public health advice to only travel if absolutely necessary".
The Department for Infrastructure was contacted by the Belfast Telegraph for a comment.