Minister for Health James Reilly has said he has no intention of resigning and criticised Fianna Fáil leader Micheál Martin for calling for his resignation at the weekend.

"I have no intention of resigning and I think it's a bit rich for Micheál Martin, the architect of the HSE, the man who, when we had more money than at any other time in the State, made a complete mess of the health service and the man who then presided for 716 weeks week in, week out, sitting at Cabinet with Bertie Ahern and Brian Cowen [who] bankrupted the country. It's really just a bit tongue-in-cheek from my point of view coming from him."

Pressure on Dr Reilly intensified over the weekend with continuing controversy over the scale of the savings earmarked in the health budget for next year.

Department of Health sources said €660 million in cuts were required to retain the current level of services. However, they acknowledged that more than that could be required to provide for unforeseen circumstances, such as a flu epidemic. On Saturday The Irish Times reported that senior health service sources believed that the level of cuts could reach €1 billion if promised but unfunded developments such as the upgrading of maternity services and the introduction of reduced hours for doctors were to be implemented.

Mr Martin claimed the figures produced in the budget had been shown to be dishonest, the Dáil had been misled and the Minister should be removed from office. He said Dr Reilly was no longer in control of the Department of Health, as officials from the Taoiseach's office and the Department of Public Expenditure and Reform were now going to be involved in supervising the health spend for next year.

Asked today if he was in control of the Department of Health's budget, Dr Reilly said: "Absolutely in control. More in control now than ever before with a new financial reform board, and the HSE with a new chief financial officer, Mr Tom Byrne, and it's precisely because of that I want these figures to be jointly assessed validated and the implications of their implementation shared and understood by the Department of Public Expenditure, Taoiseach and all my Cabinet colleagues and this is a Cabinet decision. It's one that I sought and I'm very thankful that I got agreement on and I think it's one that will help us fully understand the challenges that the health service faces.

“I think in the past there was a cause for concern in health that there was a lot of money spent that was being wasted but I think you’d have to acknowledge that having taken €3.3 billion out over the last number of years, having reduced the staffing levels by over ten per cent in the face of an eight per cent rise in population and a three per cent increase in admissions this year alone, to our emergency departments … that we face an enormous challenge.

“There is no fat left in the system. We are down to the bone and I would like everybody to understand as we go towards validating this, the implications it may have for the service plan.”

He said this verification process would determine if €666 million or more than €1 billion, would have to be taken out of the Department’s budget next year.

Minister for Children Frances Fitzgerald said there was "a collegiate approach" by the Cabinet in relation to the health budget "and we are all working together on the range of challenges that we face as a government".

Asked about the public’s concern over the loss of medical cards, following the budget, Dr Reilly said: “A very important thing to say here is to reassure people with medical cards, who nearly now number two million people between GP care cards and full medical cards, that their cards are not in jeopardy. They are legally entitled…there’s no question of us changing the rules to change that entitlement. The policy hasn’t changed and had it changed we would have had to go to Dáil Éireann and lay it in front of both Houses of the Oireachtas.”

He said it appeared that some people were not listing all their expenses when proving their entitlement to a medical card and said people should put all their expenses down, even if they did not seem to be connected to their claim.

Thousands of people may lose their medical cards in a major drive against fraud announced in Budget 2014.Dr Reilly has previously declined to say how many cards would be removed by the “probity” exercise, even though a specific target saving of €113 million is identified.

Dr Reilly was speaking today at the launch of Safefood’s childhood obesity campaign launched today.