GPs will struggle to offer same-day appointments or allow new patients to join their client list, due to changes in the budget.
That's according to the Irish Medical Organisation, which has concerns over the Government's decision to provide free GP care for 6 and 7 year old's.
Public Expenditure Minister Michael McGrath also said he intends to extend the coverage to all children under the age of 12.
Chairman of the IMO's GP Committee, Dr Denis McCauley, says medical cards should be means tested.
"I think if somebody is finding it quite hard to pay for their GP, and they can't see us - that's a situation that I don't want.
"But I think if you're giving it to an age cohort you generally will give these cards to people who could perhaps pay for this service, and that money should be spent elsewhere."
