Doubt has been cast on the government’s NHS reform drive after Liberal Democrat dissent forced health secretary Andrew Lansley to admit further changes could be made to the plans.

The situation, which arose after Lib Dems overwhelmingly voted to reject the Health Bill last Saturday, has been described as “destabilising”, and a source of “anxiety”.

The next day Mr Lansley told the BBC the government could “clarify and amend in order to reassure people”, and his plans were “always under review”.

He said: “We have already made changes. We are not sitting there going: ‘Oh, we know the answers and nothing must change’.”

NHS Alliance chief executive Mike Sobanja said the events would not affect the “general thrust” of the bill. But he said key details, such as the extent of private sector involvement, were “becoming less clear by the day”.

He said the fact the full picture would be unclear until late summer, when the bill is expected to become law, was “destabilising and difficult to manage”.

Regarding GPs who were considering whether or not to form pathfinder commissioning consortia, Mr Sobanja said: “If they feel there’s not sufficient political stability to be able to do so, they will only start getting their act together when they feel there is.”

“If there are those who want to keep their heads down until they can see the complete picture, this gives them a reason not to engage.”

NHS Confederation acting chief executive Nigel Edwards said the government was struggling to articulate what it was trying to accomplish and why.

For example, it was still unclear how GP commissioners would relate to the NHS Commissioning Board, and how powerful the board and Monitor would be.

“That is the source of some anxiety”, he said.

At the Liberal Democrats’ spring conference in Sheffield last Saturday, delegates voted almost unanimously to limit private sector involvement and rule out any price competition.

The conference also called for councillors to be given half the seats on commissioning consortium boards and for council scrutiny bodies to have greater powers to question providers.

Opening the debate, health minister Paul Burstow said: “Any change in the NHS creates fear.”

He argued that private sector involvement was “not new” and said “if there were any threat of an American-style health system I would quit the government”.