Health Secretary Andrew Lansley has admitted there is "risk" attached to his radical NHS reform plans, but believes change is essential to provide better standards for patients.
However there would be a "greater risk" if the health service was not revolutionised, Mr Lansley insisted.
Under the Health and Social Care Bill, the majority of the NHS budget will pass to GPs who will have responsibility for commissioning services for patients.
Primary care trusts (PCTs) and strategic health authorities, which commission services at the moment, will be scrapped.
Six health service unions - including the Royal College of Nursing and British Medical Association - dismissed the proposals as "potentially disastrous" earlier in January.
Speaking to BBC1's Andrew Marr Show, the Health Secretary said: "I didn't say there wasn't risk. Of course there's risk because there's change.
"But actually if we don't change, the greater risk is that these problems that we have at the moment that we have to deal with won't be solved."
The NHS budget would be increased by £10.7 billion over the next four years but spending alone was "not the answer", Mr Lansley said.
"We discovered under Labour spending money isn't the answer, we have to deliver the results for patients. We don't get the results we should compared with other European countries; if we did, we would save thousands of lives."
Copyright © Press Association 2011
Your comments (terms and conditions apply):
A side from all the practical risks like who is going to monitor the GPs,
a big risk is the fact that too big of change is going to happen too soon
without time or preparation to give it a chance of working. Many places
will move toward the changes solely based on "early bird gets the worm"
mentality. Going to PMS and fundholding in the past has shown that the
first couple of waves gets the most financial support. I think there is an
element of places moving quickly for the money but not ready for the
Dean Thompson, London