Alan Milburn has said that US and European private health providers are to become "a permanent feature of the new NHS landscape".

Speaking to the NHS Confederation on Friday, the health secretary told hospital managers that the government is to call in overseas private health sector providers in a bid to deliver on tough NHS pledges.

"The biggest constraint the NHS faces is shortages of capacity. So I can tell this conference today that in addition to sustained growth in existing NHS provision, we will bring new providers from overseas into this country in order to further expand services for NHS patients," he said.

"We are now in discussions with a number of major overseas providers to bring clinical teams - in particular extra surgeons and other doctors - to this country."

In a development that will anger Labour MPs and health unions he said the government would give the private sector a permanent role in NHS delivery.

"I will be meeting with prospective providers from both Europe and America over the course of the next few months with a view to encouraging them to invest in Britain," he said.

"Like NHS use of existing private sector providers, this is not a temporary measure. These new providers will become a permanent feature of the new NHS landscape.

"They will provide NHS services to NHS patients according to NHS principles. And in the process they will open up more choices for patients and more diversity in provision."

American health group Johnson and Johnson is to be brought in to help set up NHS "no bed, no stay units" for minor operations.

The firm runs 30 similar units in the US and the innovation is said to have increased the number of daily small-scale surgical procedures by 25 per cent.

Milburn acknowledged the scope of the "fundamental change" but reaffirmed the NHS's original public service values.

"It is also a fundamental change," he said. "Not in how the NHS is funded or the values on which it is founded, but in how it is organised. NHS healthcare no longer needs to always be delivered exclusively by line managed NHS organisations".

He praised the work of health service managers for keeping the "agenda for change" on course.

"It's a year since I last spoke to you. Those twelve months have been a time of great change and major challenge for the NHS and the people who work in it, lead it and manage it," he said.

"When changes were first proposed some said they were too risky. It is certainly true that at a time when the NHS is focussed on delivering a major programme of improvement there were risks associated with making these changes.

"But the transition has gone better than many feared."

Describing the NHS focused budget as a "once in a lifetime opportunity", Milburn acknowledged that heath reform would bring pain.

"As we expand services there will be growing pains along the way. But that is precisely what they are. The pains that come from growth.

"So no one should fall into the trap of saying that these unprecedented resources somehow bring problems when in fact they present the NHS with a once in a lifetime opportunity," he said.

Milburn was earlier confronted by figures suggesting that the productivity of NHS consultants - key to reducing waiting lists - was falling.

BBC's Today programme featured statistics from the NHS's Birmingham management centre revealing that the number of patients treated in general surgery dropped by a fifth over the last six years.

Health experts consider the drop in productivity to be caused by a Whitehall imposed red-tape burden and defensive medicine as risk-averse doctors seek to avoid litigation.

New guidelines preventing junior doctors from working long hours, are also said to have contributed to the drop in operations.

Milburn told the programme that the figures could be misleading - especially if the public assumed that top doctors were doing less work - and should be taken in the context of an overall increase in good NHS outcomes.

"It would be wrong to give the impression that somehow or other NHS consultants aren't working hard for the NHS overwhelmingly they are, and they are actually contributing to an increase overall in the number of operations and reductions in waiting times," he said.

The health secretary said that an apparently negative drop in individual productivity is generated by two positive developments - better quality and more operations.

"Overall the number of operations is increasing. Waiting times are falling. There is an awfully long way to go but at least they are moving in the right direction," he told the BBC.

"Quality is improving and you can see that most graphically in the death rates following surgery, which last year fell by five per cent."

And on the question of individual productivity, Milburn reminded doctors that "there are some issues here, and we are currently re-negotiating the consultant contract with the British Medical Association".

Acknowledging the paperwork burden for NHS staff, Milburn promised that medics would be given support staff.

"I think there is an issue about the amount of direct clinical time with patients," he said.

"We have got to help release some of the burdens on consultants, for example by providing them with better administrative and IT support, so if you like you can get a better balance between the quantity of patients being seen and the quality of care that is being given."