Andrew Lansley heckled by June Hautot in NHS protest
David Cameron has said there "are a few myths we need to bust" and pledged to push ahead with his NHS changes after his health secretary was heckled and jostled outside Downing Street.
Andrew Lansley was greeted with shouts of "shame" as he headed for a meeting inside No 10 about the NHS.
After the meeting, the prime minister said reform was "never easy".
Groups including the British Medical Association and Royal College of Nursing say they have been excluded.
Proposals in the Health and Social Care Bill include giving GPs control of much of the NHS budget and opening up the health service to greater competition from the private and voluntary sector. These have proved controversial.
On Friday, members of the Royal College of Paediatrics and Child Health joined several Royal Medical Colleges, including the Royal College of GPs, in calling for the bill to be scrapped.
Unions and professional bodies, including the British Medical Association (BMA), the Royal College of Nursing (RCN) and the Royal College of Midwives, are also among those who want it to be withdrawn.
The government said the Downing Street meeting was designed for those "constructively engaged in implementing the modernisation".
As he arrived, Mr Lansley was shouted at by several protesters waiting by the gates of Downing Street.
One woman, June Hautot, a former Unison rep, barred his way, telling the health secretary: "I'm not getting out of the way."
Mr Lansley told her that the NHS was not being privatised and said waiting lists were down.
She also appeared to prod Mr Lansley, who was forced to walk around her to get to a gate to enter Downing Street.
Afterwards, Mr Lansley described the confrontation as "sticks and stones" and insisted he was determined to stick with the planned reforms.
Speaking after the incident, Ms Hautot told the BBC: "The NHS is supposed to be from cradle to grave. It doesn't matter who's in power; we're here to save the NHS."
Another protester, London GP Louise Perkins, said: "Cameron is misrepresenting us by saying he has GP support. He doesn't. You could get the number of supporters into a telephone booth."
Asked about the protest after the meeting, the PM said: "Reform is never easy, but it is vital to reform our NHS because I want it to be there looking after every family in the country and doing a good job into the future.
"We had a constructive and helpful meeting and what's clear is that there are quite a few myths that we need to bust about this reform.
"Choice for patients is a good thing: making sure that GPs, not bureaucrats, are making decisions, that's a good thing.
"So there are myths we need to bust, but I also heard how, on the ground, where some of the reforms are already taking place, you are actually seeing better health outcomes, GPs doing more things for their patients, people living healthier lives as a result of these changes."
During a visit to a hospital in Romford, north London, later in the day, Mr Lansley said his door was "always open" to groups like the BMA and the RCN who were not invited to the earlier meeting.
Earlier Peter Carter, from the RCN, told BBC Radio 4's Today programme: "We really don't think it's a sensible way forward to think that you can have a meeting which has been called an emergency summit to take things forward without involving many of the key organisations that are intrinsic to making sure the NHS is successful."
In a statement on the meeting, the British Medical Association said: "It would seem odd if the major bodies representing health professionals were not included."
And Sarah Gorton, the senior national officer for health at the public sector union Unison, said: "Health workers should have their voices heard when major changes to the health service are being discussed."
A Downing Street spokesman said the prime minister had no plans to meet health groups opposed to the NHS changes, but added that he was "listening to health professionals about how we can implement the reforms we have set out".
He said the government had held "countless meetings with health professionals and would continue to do so".
At the meeting the prime minister was expected to point to evidence that emergency hospital admissions had fallen year-on-year for the first time.
Department of Health figures show a 0.5% decline in 2011, compared with a 36% increase between 2001 and 2010.
The BBC News Channel's chief political correspondent, Norman Smith, said the government felt the time for "tweaking, amending and altering" the health bill was over and that there was no point continuing to "talk to those health groups they felt were pretty much decided against the changes".
Labour opposes the bill and party leader Ed Miliband said: "This bunker mentality is the wrong way to run the NHS...
"It's not too late to start listening to the doctors, the nurses and the midwives. It's not too late to listen to patients."