Bus drivers say they won't take on passengers at Busáras after dark unless security's improved there.
It's after an alleged assault on a driver there two weeks ago.
National Bus and Rail Union members will refuse to pick up and drop off passengers after 8pm from 16th of September if there's no action.
And they'll take action sooner if there's another incident.
Dermot O'Leary from the NBRU says drivers have to make sure they're safe.
"There's been a number of assault at Busáras over the last number of months and only last week another serious assault on one of our colleagues," he said.
"This is not industrial action, this is about health and safety and as far as our members are concerned both the Company, Bus Éireann, and indeed the government, have a duty of care to them and the people they carry from A to B."
