Bus Eireann is to consider withdrawing services in Waterford city after 6.30 p.m. following a number of attacks on vehicles.
In the most serious incident, a brick was thrown through a window of a bus in the St John's Park area of the city, one of four such attacks on Monday evening. None of the passengers was injured.
Mr Pat Crowley, the company's south-east area manager, said there had been a number of isolated stone-throwing incidents in the past, but the latest spate of attacks had forced him to consider withdrawing night-time services.
"I know that would mean letting down the majority of people because of the wanton vandalism of a few blackguards, which would be a pity," he said. "But we cannot allow passengers or drivers to be put at very serious risk."
"For a brick to be thrown through a double-glazed window takes a lot of strength, and it could not have been done by a small child. It could have caused very serious injury."
Mr Crowley said he did not know if the attacks on Monday night, which involved the throwing of stones and eggs, were related to the Hallowe'en festivities of the night before, but the situation would be closely monitored for the remainder of this week before a decision on the future of services was taken.
The damage caused by the St John's Park attack would cost about £2,000 to repair. A partial withdrawal of services about three years ago following similar attacks had proved effective, he said. "We will have to contact the residents' associations to see what can be done, but things cannot continue as they are."
The company operates four bus routes in the city, with services currently running until 11.30 p.m.
