Almost a third of employers have revealed they expect staff to call in sick after St Patrick's Day celebrations.
A survey showed some 29pc of workers are likely to be late into the office on Friday morning, with 94pc of bosses fearing productivity will fall on the day.
Alan Price of employment law consultancy Peninsula Ireland, which carried out the survey, said many employees will be looking to pull a sickie and have an unofficial long weekend.
"St Patrick's Day is a huge celebration for the people of Ireland, but for many bosses the following day is one of lost productivity, something they could do without in the current economic climate," he said.
"If employees turn in late for work or do not turn up at all, they should be disciplined in the same way as they would be on any other day."
A total of 626 employers from a wide variety of industries were questioned for the survey.
Meanwhile, drinkaware.ie published a survival guide to ensure revellers do not turn the wrong shade of green.
It advised people to start the day with a decent meal and to eat between drinks, avoid large rounds, pace themselves and not to drive the morning after.