Bus drivers say they will not take on passengers at Busáras after dark unless security is improved.
The National Bus and Rail Union (NBRU) is warning its members will start the practice at the Dublin station from September 16 if action is not taken.
They added that action would be taken sooner if there is another incident.
Dermot O'Leary from the NBRU says driver safety is the main priority.
"There has a number of assaults at Busáras over the last number of months and only last week another serious assault on one of our colleagues, an NBRU bus driver," said Mr O'Leary.
"Our members are coming to us and saying this is not industrial action, this is about health and safety.
"As far as all members are concerned both the company, which is Bus Éireann in this case, and the government have a duty of care to both themselves and the people that they carry from A to B."