A staff representative for the Dublin Fire Brigade said that he doubted enough firefighters would be on to keep up with demand on Halloween night tonight.
Luke McCann said that the service has not had enough people on during the holiday "for a number of years".
Speaking on RTÉ's Today with Claire Byrne he said: "We are consistently understaffed; we have difficulty filling fire engines, and that has an effect on how we respond to emergencies."
In response a spokesperson for the fire brigade said that an intensive recruitment campaign is currently under way, and added that was fully staffed on Halloween night last year.
Mr McCann reiterated that he felt they would not be fully staffed later.
Mr McCann said: "If we are fully staffed tonight, that is a good thing for my colleagues it means that we can work safely, and we can look after public safety much more effectively."
Last year there were 234 fire callouts on Halloween night, with 169 of those related to the holiday.
The fire brigade also attended 357 ambulance calls.
