Liberal Democrat leaders are trying to douse a growing revolt over the coalition's controversial NHS reforms.

Party critics claim the reforms will increase health inequalities, make tracts of the NHS unviable and simply provide profits for private firms asked to take on the task of commissioning care.

The backlash comes as figures show the reforms will cost £1.8bn to implement. The Department of Health today revealed it had sought authorisation from parliament to set the money aside to cover redundancy payments, pension liabilities and the penalties of breaking contractual obligations of the primary care trusts that will be abolished under the plans.

But the political backlash poses the greatest risk for the coalition as Lib Dem rebels attempt to raise it at their spring conference next month.

Privately many cabinet members have doubts about the politics of coalition health reforms, if not the reforms themselves, and rejection of them by one wing of the coalition would only increase those doubts.

Almost all ministers acknowledge that the need for the highly complex reorganisation has not yet been sold well.

A motion calling for Lib Dems to rethink the reforms has not formally been tabled for conference debate by party officials after the Lib Dem health minister Paul Burstow voiced criticism of its "inaccuracies".

He believes critics of the reforms have misunderstood them.

Officials have instead given preference to a motion tabled by Burstow that welcomes the reforms, including GP-led commissioning and contends the NHS needs reform after a decade of Labour failure.

Yet party critics of the reforms will now decide whether to amend his motion or try to vote it down. They also plan to hold a fringe meeting at conference rallying opposition to the changes.

One critic, Charles West, a GP, former NHS general manager and Lib Dem parliamentary candidate for Shrewsbury at the last election, said: "The wholesale removal of primary care trusts and strategic health authorities is enormously disruptive and risky. The biggest danger is that opening up whole parts of the NHS contracts to the concept of any willing provider will mean that private providers will pick and choose those contracts that are easy and profitable, which means the residual NHS bodies will no longer be viable."

West insisted: "I am loyal to the Liberal Democrats, but I also love the NHS, and these reforms go in the wrong direction. The NHS needs improving, but the record shows it is not in the state described by the coalition, as authoritive institutions such as the King's Fund have shown." He said patients with some of the most difficult healthcare requirements, such as elderly patients with multiple medical conditions, were likely to benefit the least from a competitive market.

Burstow has been battling to dispel what he regards as myths about what the government is proposing.

He insists some of the criticisms of the bill are based on myths and misunderstandings. He says very few GPs will be asked to be involved in commissioning.

The NHS commissioning boards will draw up contracts. Best practice tariffs will be drawn up to secure the best price and there will be an economic regulator to oversee pricing and to ensure the NHS provision of services operates within the public interest.