The Taoiseach has denied that the Government was reneging on promises to provide 200,000 extra medical cards even though more than 100,000 have been taken out of the system.
Labour Party leader Mr Pat Rabbitte claimed there were thousands of people on low incomes who were in pain but were too afraid to go to the doctor because they could not afford it.
He asked: "How in the name of God can you justify that situation in such an extremely affluent economy?"
Mr Ahern accepted that the Government had made a commitment to extend eligibility for medical cards and said it was one they would try and fulfil.
He told the Dáil that 1.1 million people, 30 per cent of the population, had medical cards.
"It is a very costly area and we will target the people most in need," he said. "The Government accepts there are people in a hard position but extending eligibility is a very costly factor.
"When medical cards were given to the over 70s the cost was far higher than projected."
Mr Rabbitte said he needn't explain how grave the situation was when 101,279 cards had been taken out of the system despite the Taoiseach's solemn pledge to provide an extra 200,000 cards in May 2002.
"People on the minimum wage can earn €280 for a 40-hour week and yet a single person earning above €143 can't get a medical card," he said.
"How can you have the hard neck to bring Fr Sean Healy down to Inchydoney and be professing compassion in circumstances when a parent on that kind of income cannot take a sick child to the doctor.
"Can you imagine having to pay that out of such paltry, low pay?" Mr Rabbitte asked.
He said a third of all employees in Ireland were not liable for income tax because they were on less than 90 per cent of the minimum wage.
He said the huge problem of low pay did not correspond with the numbers of people who were not eligible for a medical card.
The Irish Medical Organisation claims medical cards should be issued to everyone on or below the minimum wage and has urgently called on the Government to make the promised 200,000 medical cards available.