Suspicions of full-scale NHS privatisation have been fuelled by a government advert apparently inviting firms to take control of NHS budgets.
GPs and hospitals are already facing greater private sector involvement
Local health managers working for bodies called primary care trusts currently buy in services, although in some areas it has been devolved to GPs.
But adverts have gone out appearing to ask for firms to take on the role.
As news broke of the move, ministers pulled the ads, saying they were wrong to imply firms could run PCT services.
THE PRIVATE SECTOR IN NHS
Operations - Nearly 10% of NHS non-emergency ops are carried out by the private sector in either private hospitals or clinics set up to carry out minor surgery
New buildings - Contracts signed to build hospitals or community buildings with NHS providers effectively paying off a mortgage over forthcoming years
Family doctors - Ministers want to see private firms run GP services, first deal already signed
The advert, appearing in the Official Journal of the European Union, said it wanted firms to set out how they could run "a comprehensive range of management services including PCT management and related services".
Instead, the government said it was only looking for firms to provide expert advice to PCTs and it would be up to local officials to decide if they wanted to use the private expertise.
But the denial has not soothed fears outsourcing PCT services is the latest step in a greater reliance on the private sector.
Nearly one in 10 NHS operations are already carried out by the private sector in either hospitals or specially-designed clinics called independent sector treatment centres which carry out minor procedures such as cataract operations.
And last month the first deal was signed in east London for a private firm to run GP services are more are in the pipeline.
Outsourcing the role of PCTs, which control three-quarters of the NHS budget to buy in services from hospitals, GPs and other community services, would complete the triangle.
Karen Jennings, head of health at public sector union Unison, said: "It is hard to see it as anything other than privatisation by stealth.
"The Department of Health have clearly taken their eye off the ball and the pace and scale of NHS reforms is leading to serious errors."
'Conflict of interest'
And Alex Nunns, of the campaign group Keep Our NHS Public, added: "We are getting into a situation where private firms could be in charge of commission NHS services and running them.
"It is a conflict of interest as it is not unimaginable that private firms will send patients to private hospitals."
And Liberal Democrat health spokesman Steve Webb MP said the episode "typifies the government's reckless approach to health reforms".
"Once again health policy is being changed by stealth without consultation, bypassing parliament, bypassing professionals and bypassing patients.
"These secret plans represent a fundamental shift in what the NHS is."
Shadow Health Secretary Andrew Lansley said the government was right to use the private sector, but was going about it in a confused manner.
Health Secretary Patricia Hewitt denied it amounted to privatisation of the NHS.
She said: "PCTs are and will remain public, statutory bodies responsible for using their growing budgets to commission the best possible services for local people.
"They can never outsource this responsibility, or ask others to make these decisions for them."