The Government is considering a prescription charge for medical card holders, the Minister for Health has indicated.
Mary Harney said that a charge of 50 cent per drug prescribed was one option being examined.
Speaking on RTÉ's The Week in Politics, the Minister also said there was a need to guard against the over-prescription and over-use of medicines.
However, Labour spokeswoman on health Jan O'Sullivan said such a prescription charge would single out those least able to pay.
"Labour accepts that there is a massive problem that needs to be addressed and that a budgetary gap of €4bn will have to be closed this year, but we do not accept that those who are least well off, such as people who are on the GMS scheme, should be forced to shoulder the burden," she said.
"A charge such as the one suggested by the Minister today, will simply mean that those on the lowest incomes will be singled out and forced to pay what amounts to yet another stealth tax."
Ms O'Sullivan said the Government should instead create a third rate of tax for those earning more than €100,000, "a proposal that the Government appears to have dismissed out of hand".