DOCTORS have warned that some GPs may not be able to operate the free scheme for five-year-olds and under.
The National Association of General Practitioners (NAGP) said that its members might not sign up over fears it would not be properly funded.
Although the organisation initially welcomed the scheme, it now believes it is merely an extension of the current medical card programme.
NAGP chairman Dr Andrew Jordan claimed that the budget of €37m meant that there was insufficient funds to make it a high-quality project.
"We thought, in good faith, that they were going to announce a scheme that was likely to deliver a high-end service," Dr Jordan said.
"Unfortunately, in the Budget, the figure of €37m was rolled out and we realised this was just an extension of the present GMS, which of course is not a top-end service, and therein lies the problem.
"It is not a question of opting out. Any doctor can decide to take a particular contract or not to take it."
Dr Jordan added that he believed the new plan would would result in a two-tier system – a full medical card and a GP card – for five-year-olds and younger.
And he claimed on RTE's Morning Ireland that the scheme came against the backdrop of millions of euro being taken out of the Budget for the GMS programme.
Dr Jordan indicated that the free GP care project for all children under five would be a separate contract that doctors could decide to avoid taking up. He also criticised reductions in funding for existing medical card schemes.
"The total GP budget to take care of the sick and the vulnerable is €440m – this is quite catastrophic," he said.
But he rejected reports that suggested doctors were claiming for deceased patients.
He said a death certificate was filed with the HSE when a patient died, including an individual's PPS number.
"If doctors were claiming payment for deceased patients, you're saying that the HSE is incompetent I don't believe for a second that the HSE is incompetent," he added.
"It would be incredible to think that they're not able to cross off the medical card when they have the information in front of them."