David Cameron is to unveil a number of guarantees in a bid to convince the public and healthcare workers that the NHS remains safe in his hands.
He will pledge that his government will not "sell-off" the NHS as well as announcing five personal guarantees designed to get patients and healthcare professionals onside.
The speech comes as the government pushes to attract support for its controversial reform plans for the health service.
Among the guarantees will be a promise to spend more while maintaining universal healthcare coverage. He will also suggest that healthcare will not be remodelled on an American-style private system.
Mr Cameron will declare that he would be "personally accountable" for ensuring that the guarantees are met.
But Labour said that he had already failed to protect NHS spending, resulting in "chaos, confusion and damage to patient care".
In his speech, Mr Cameron will insist that NHS modernisation remains essential to prevent the service "buckling" under the strain of dealing with the demands of an ageing population.
At the same time he will acknowledge the need for the government to take both the public and healthcare professionals with them over the reforms which would hand over commissioning powers to GPs and extend private sector provision.