Dublin Fire Brigade (DFB) has responded to 5,246 hoax and false call-outs over the last five years, the Herald can reveal.
A total of 1,245 hoax calls, known as malicious false alarms, have been made since the start of 2011.
And 3,971 "false alarm good intention" reports were made in the same period.
Records released by Dublin City Council show that 183 malicious call-outs have been responded to by the DFB so far this year.
A total of 766 false alarms with good intention were responded to in the same period.
DFB senior executive officer Brendan Hayden said hoax calls affect the resources available for genuine call-outs.
And he called on the public to respect members of the emergency services.
"Malicious false alarms result in unnecessary call-outs which could adversely impact on genuine calls for assistance," he said.
"DFB actively discourages such acts through various community fire safety initiatives and communication channels and always ask the public to respect all emergency services.
"Due to the nature of the emergency services, fire cover must be provided at all times, and this includes responding to all types of emergency incidents."
The figures released by the council only take into account hoax and false call-outs that were responded to by the emergency service.
Since 2011, the DFB has responded to 12 river rescues that turned out to be malicious false alarms.
In these cases, it takes emergency services several hours to determine that a report was in fact a hoax, resulting in an unnecessary waste of hours and resources.
There were 480 hoax small fires and 110 malicious false alarm car fires were reported between 2011 and 2015.
Almost 300 hoax domestic fires were also reported in the same period
Under DFB's charging system, the service would have sent out bills worth more than €2m for that number of calls if they had been real emergencies.
Domestic charges and charges for attending the scene of a car crash stand at a rate of €500 and €610 respectively.
Owners of commercial premises are charged from €610 for an initial call-out to €915 for emergencies involving hazardous substances.
DFB could not provide the cost of the hoax and false alarm call-outs.
"The cost of responding to all incidents is provided in the annual budget," said Mr Hayden.
"Staff are on duty to provide fire and emergency cover so there is no loss to Dublin Fire Brigade."