Bus Éireann City and Express Services in Waterford have been cancelled because of unofficial action by bus drivers.
A spokeswoman for Bus Éireann told ireland.comsaid no warning was given about the stoppage, which began this morning.
She said a meeting had taken place last week between management and staff to address concerns over resources and that a further meeting is due to be held next week.
"There is a process under way to resolve certain operational issues in Waterford, and the company is disappointed that some people chose to opt out of this process and engage in an action that is detrimental to our customers," she said.
She said Bus Éireann was not in a position to make alternative arrangements for passengers and urged those planning to use the city's bus services to contact Waterford bus station.