SIPTU has called for the urgent introduction of transport police following an alleged attack on a bus in Dublin last Friday.
Dublin Bus said the incident took place on the N4, which operates between Point Village and Blanchardstown.
SIPTU spokesperson for the Respect Transport Workers campaign Suzanne Armstrong said incidents on public transport are happening "more and more frequently".
Speaking on RTÉ's News at One, she said the driver was shaken after witnessing a passenger be beaten by a group of youths.
"There was blood everywhere and that poor woman was stuck in her cab, nowhere to go and had to witness that," she said.
Ms Armstrong said SIPTU wanted to establish a stakeholder forum with unions, the companies, the police department and the Government.
The union also called for "specialised transport police".
Ms Armstrong said that whenever a guard or security personnel steps on the bus, there is "no hassle on it that day", adding that the aforementioned incident would not have taken place if there was a transport police force.
"Unfortunately, I think most drivers across all public transport have had experience of this," she said.
"Be it fights breaking out on the bus, anti-social behaviour, drug use, racial abuse, it is just more and more frequent."
Ms Armstrong said that while working as a driver, she has seen bricks thrown through windows, fights, drug deals and use, and witnessed racial abuse.
"What can we do? We can call for the guards, but by the time the guards get there... I mean their resources are thin on the ground, and anyone who is involved is off the bus."
A recent SIPTU survey found there has been an increase in anti-social behaviour since COVID-19.
"You do not know what you’re going to face going to work, myself and my colleagues," Ms Armstrong added.
"You go into work, and you have no idea what is going to happen you on the day, and that can be terrifying."
