Andrew Lansley has brushed off suggestions that he should sacrifice himself to ensure the survival of the coalition's controversial NHS reforms.

The Health Secretary hit back following reports of criticism from Tory Cabinet colleagues over his handling of the shake-up.

Asked if it was time he resigned in order to save the changes, Mr Lansley told journalists: "No, it is not. Because actually we as a Government have committed to supporting the NHS. This legislation has been supported by the House of Commons, by the House of Lords."

After delivering a speech in Edinburgh, Mr Lansley went on: "It is not about the Bill as such, it is about what the Bill enables the NHS to achieve in the future. That is not about me, that is about us as a Government."

He added: "It is because the NHS matters so much, because we believe in the values of the NHS, we have to be prepared to reform."

The latest wave of speculation over Mr Lansley's future was sparked when Tory grassroots site ConservativeHome claimed three Cabinet ministers had privately "rung the alarm bell" about the shake-up. One apparently called for the health secretary to be replaced, another said the Bill should be dropped, and the third likened the NHS reforms to the poll tax.

Editor Tim Montgomerie wrote: "David Cameron's greatest political achievement as leader of the opposition was to neutralise health as an issue. The greatest mistake of his time as Prime Minister has been to put it back at the centre of political debate."

Party co-chairman Baroness Warsi and health minister Simon Burns were quickly mobilised to try to shore up Mr Lansley's position. Mr Burns told BBC News: "To be quite frank, they are all unnamed - I regard it as tittle-tattle.

Labour leader Ed Miliband said: "Nurses, doctors and patients have been telling David Cameron for months that he's on the wrong track on the NHS. Now even members of his Cabinet are telling David Cameron that he is making a profound mistake on the NHS."

Mr Miliband has written to all members of the House of Lords urging them to block key measures in the Bill. "On behalf of my Party, I want to extend this offer to peers of all parties and of none - we will work with you to stop this Bill damaging the NHS," he wrote.