Twenty-five deer were culled at Dublin’s Phoenix Park on Thursday, the Office of Public Works (OPW) said.
Fallow deer have no natural predators in Ireland and it is necessary to control numbers, the Government department said.
Campaigners said officials were trying to make money through the sale of meat and added contraceptives should be used instead.
The Alliance for Animal Rights said: “People have not the empathy but surely we should be promoting peace and not this slaughter?
“Most normal people care about animals if they see them suffering – all this is going on with our taxes.”
The Phoenix Park was established as a Royal Deer Park in 1662.
The OPW said: “Fallow deer have been in the park ever since and have been sustainably managed over the centuries.
“The OPW takes deer welfare very seriously.”
It said if animals were not removed, food would become scarce and more animals would ultimately suffer.
“Without population control there would be other welfare issues such as low body fat, malnutrition and high incidence of death from exposure to cold in winter.
“Attempting to maintain too many deer within a restricted park area would soon lead to a build-up of parasites and other pathogens causing disease in the deer.
“Public safety would also be a serious concern if the population is not maintained at the current numbers.”
The OPW does not administer contraceptives through feed or injections and there are no contraceptives licensed for use in free-living deer in Ireland.
Campaigners said there were examples of contraceptives used in the Rocky Mountains in the US which could last for several years.
The cull was carried out under licence from the National Parks and Wildlife Services, (NPWS) and in conjunction with the School of Biology and Environmental Science, UCD, and overseen by a vet.
The OPW added: “We regularly monitor the worldwide development of technology to limit deer populations and will continue to keep our policies for the management of deer under review.”