David Cameron will launch a fresh bid to shore up support for the health service reforms this week, as a political showdown looms over the controversial set of changes.

The prime minister will defend the shake-up in a speech, which is reported to include five guarantees about the future of the health service.

The Daily Telegraph said his series of personal pledges would include keeping waiting lists low, maintaining spending and no privatisation.

Others would be ensuring patient care was properly co-ordinated and that it remained universally available and free at the point of delivery, the newspaper said.

Mr Cameron will reassert the message that reform is inevitable if the health service is to survive massively rising costs - but that ministers are responding to criticisms of the blueprint.

Health secretary Andrew Lansley indicated last week that he was ready to accept “substantial and significant” changes to the plans, which he set out in January’s Health and Social Care Bill.

NHS reform has become a battleground within the coalition in recent weeks, with deputy prime minister Nick Clegg making it a test of his promise to show a more muscular influence on policy.

The passage of the legislation had been “paused” for a month while further consultation took place.

Conclusions from that process will now be presented to ministers later this month but Mr Clegg has warned his Liberal Democrat MPs will not approve the bill unless it is significantly watered down.

Increasing the involvement of the private sector and competition is strongly opposed by many party activists, who voted heavily against the package earlier this year.

A Downing Street source confirmed that Mr Cameron was to make a speech on the reforms tomorrow but would not comment on its exact content.