David Cameron is facing pressure to allow healthcare professionals to take party in a summit on NHS reforms.
Labour leader Ed Miliband accused the Prime Minister of failing to listen to the experts as it emerged major bodies critical of the proposals have not been invited to the Downing Street meeting on Monday.
Mr Cameron called the summit to discuss the implementation of the Health and Social Care Bill, which faces intense opposition and has yet to reach the statute book.
But some organisations most critical of the bill, such as the British Medical Association (BMA) and the Royal College of General Practitioners, appear not to have been invited.
Downing Street would not disclose who had been invited to attend the meeting, saying only that it was a "range of national healthcare organisations and clinical commissioning groups".
A spokeswoman said it was being held "to discuss implementation of the health reforms with representatives from a range of national healthcare organisations and clinical commissioning groups. "This forms part of the Government's ongoing dialogue with health practitioners about the implementation of these reforms."
The BMA said it would be "odd" if bodies representing health professionals were not invited to the summit.
"The BMA does not appear to have been invited to an NHS summit at Downing Street next week," a spokesman said. "If there is such an event, it would seem odd if the major bodies representing health professionals were not included."
The Chartered Society of Physiotherapy (CSP), another opponent of the bill, said it had not been invited to the summit.
Chief executive Phil Gray said: "It is extremely concerning that many of the key professional bodies and healthcare organisations, which will be expected to work with the changes that the bill will bring, have been excluded from what is clearly a crucial meeting."