The Royal College of Physicians has criticised "Arthur's Day", an event organised by drinks manufacturer Diageo, saying it promotes heavy drinking and is irresponsible.
The criticism comes after singer Christy Moore wrote a song describing the event as an "alcoholiday".
Diageo said it is a unique music event and the company discourages alcohol misuse all year round.
Over 500 music events featuring over 1,000 different acts will be held across Ireland on Thursday.
Meanwhile, Fianna Fáil Senator Averil Power has called on Diageo to cover the financial cost of the additional public services needed to manage the event.
She said the taxpayer should not have to cover the costs of the extra gardaí required to police the event and the major clean-up operation the following day.