Management at Cinnamon restaurant in Ranelagh have apologised after a staff member called a customer an "arsehole" on Twitter.
The staff member used Cinnamon's Twitter account, which only has 11 tweets to make the statement after the customer complained of having to wait 40 minutes for service and referred to the restaurant as "a pretentious crèche".
The customer also tweeted that he would not be returning to the restaurant. The staff member responded with: "Here's something else for you to re tweet. You're an arsehole. Why don't you come in and introduce yourself to us."
A member of management said the member of staff had experienced a "moment of madness" that was unprofessional.
"I concede that it was not a professional move to make and was not as jovial as intended," she said.
"To be honest, I am not really sure what the next move should be."
Six hours after the offending tweet was published, the restaurant apologised publically and said disciplinary action has been taken.
"In Cinnamon the customer is our priority, we have a huge number of regular customers, many of whom have now become our friends. We sincerely apologise to all of our customers for the offence caused by our comments on Twitter."
Since the tweet was posted earlier today, Twitter users have lambasted the restaurant's social media blunder, which has already received over 100 retweets.
Restaurants Association of Ireland chief executive Adrian Cummins said it is important to have a good relationship with all customers.
"The customer is king at the moment and there is a need to address complaints in an organised fashion and expletives are not the way to go about it," he said.
He also advised other restaurants to use social media wisely.
"I advise all our members to be careful what they tweet. We need to be careful how we use the power of social media."