NHS Confederation chief executive Steve Barnett said the party had yet to provide details of how the policy would work, adding: ‘At some point it's got to provide that.'
At a briefing in Westminster last week he said it was a ‘step too far to say GPs have the skills and knowledge to make good commissioning decisions'.
David Furness, leader of the health project at the Social Market Foundation think-tank, added: ‘Practice-based commissioning hasn't worked. There are only a few GPs that want to do it, and only a few of them that are any good.'
He called for PCTs' commissioning role to be strengthened, by making them answerable to patients rather than politicians.
RCGP chairman Professor Steve Field noted that GP training did not currently include commissioning.
In a separate interview, shadow health minister Mark Simmonds stood by the policy. ‘Commissioning at PCT level is very patchy, to say the least,' he said. ‘The people who understand the patients best are GPs. Therefore they're in the best place to understand what the needs of their communities are.'