Andrew Lansley, the health secretary, has acknowledged that people have "genuine" concerns about his reforms to the NHS as he announced that the government would table amendments to the bill.

Amid fears in Downing Street that Lansley has failed to explain the thinking behind his reforms, the health secretary said he would use a "natural break in the passage of the bill" to offer reassurances that the government's sole intention is to improve the NHS.

In a statement to MPs, Lansley announced a series of areas where the government would make improvements. They are:

• Choice and competition. "Choice, competition and the involvement of the private sector should only be a means to improve services for patient, not ends in themselves. Some services like accident and emergency or major trauma clearly will never be based on competition."

• Private sector involvement. "People want to know that private companies cannot cherry pick NHS activity, undermining existing NHS providers. But competition must be fair."

• Transparency of new GP-led consortia that will control 60% of the NHS's £103bn budget. "People want to know that the GP commissioning groups cannot have a conflict of interest, are transparent in their decisions and accountable not only nationally but locally, through the democratic input to health and wellbeing boards."

Lansley said 220 GP-led commissioning groups had already applied to be "pathfinder commissioning groups" covering 87% of the population of England. But he acknowledged that the pace of reform had caused concerns.

"We recognise that this speed of progress has brought with it some substantive concerns, expressed in various quarters. Some of those concerns are misplaced or based on misrepresentations but we recognise that some are genuine.

"We want to continue to listen to, engage with and learn from experts, patients and frontline staff within the NHS and beyond and to respond accordingly. I can therefore tell the house that we propose to take the opportunity of a natural break in the passage of the bill to pause, to listen and to engage with all those who want the NHS to succeed and subsequently to bring forward amendments to improve the plans further in the normal way."

Nick Clegg is also nervous about the reforms, which appear to run counter to the pledge in the coalition agreement to "stop the top-down reorganisations of the NHS". Liberal Democrats voted against the reforms at their recent spring conference.

Lansley's plans would transfer about 60% of the NHS budget to GP commissioning consortiums, abolish primary care trusts, appoint an independent NHS commissioning board and extend a regulated market in healthcare provision.

Cameron's spokesman insisted the thrust of the reforms was correct, but added that ministers would use the Easter break to put the bill on hold. The announcement of a delay was agreed at a meeting involving Cameron and cabinet colleagues on Thursday.

The spokesman said: "We have got to a certain point in the bill. Committee stage [in the Commons] has been completed. There is a break now.

"[The health secretary] is going to be setting out the next steps. We have a very clear objective in reforming and modernising the health service. We intend to push ahead with this."

The statement by Lansley follows the Policy Exchange warning that the health and social care bill's proposals to abolish every primary care trust (PCT) by 2013 "could lead to the new structure simply replicating the existing system in all but name".

The report, entitled Implementing GP Commissioning, is based on interviews with the GP leaders or managers of 16 "pathfinder" consortiums, and with other experts.

Its findings will add to pressure on Cameron to rethink how he sells the reforms and whether they should go ahead at the pace planned, given the growing hostility from GPs. Some of the Policy Exchange ideas would require radical recasting of commissioning.

The study concedes that "the government has lost many potential supporters inside and outside the NHS", and blames the Department of Health for not winning over GPs.

It also questions "whether GPs have the necessary skills to run such highly complex operations before the transition to GP commissioning takes places".

Eve Norridge, the lead author of the report, said: "There are many GPs who have the potential to become highly successful commissioners. It would be a loss to everyone, especially patients, if the policy were discredited due to overly hasty implementation.

"Ministers need to address GPs' concerns before loading such huge new responsibilities on their shoulders.

"The danger is that GPs take part so reluctantly in the new scheme that it ends up replicating the existing model rather than becoming the new and innovative system the government desires."

The Department of Health has insisted that applications to join the pathfinder projects show real support for the ideas contained in the bill, but others argue that GPs have merely bowed to what they regard as the inevitable.