Sessional GPs are being shut out of developing consortia across England, according to the National Association of Sessional GPs (NASGP).
GP consortia are failing to engage sessional GPs through 'sheer ignorance' or because they cannot contact them directly, said NASGP chairman Dr Richard Fieldhouse.
The BMA has said sessional GPs may be well placed to take up roles in consortia because working across multiple practices gives them a 'unique understanding' of local patients.
Evidence is emerging that some consortia are building links with sessional GPs.
But Dr Fieldhouse said that despite locums having the time and local knowledge to fill commissioning roles, few had been given the opportunity.
'The White Paper states it will be GP practices running the show and many partners seem to be taking that to mean they can actively exclude other GPs,' he said.
'For others, it hasn't even crossed their mind to contact local locums, through sheer ignorance. Some consortia simply write to practices and hope they will pass information on to their locums when they bump into them.'
Dr Fieldhouse said many of the problems are caused by the lack of an up-to-date database of sessional GPs.
A survey by the NASGP last winter found just one in five of its members received urgent cascade emails from their PCT during the swine flu outbreak.
But not all consortia have failed to engage locums and some have sessional GPs in senior commissioning roles, said Dr Fieldhouse.
The Newcastle Bridges GP Commissioning Consortium is among consortia that have developed processes to hear the opinions of locum GPs.
Its productivity lead Dr Mike Scott said the consortium holds Dragons' Den-style forums where sessional GPs can pitch ideas to the board.
'The programme implementation group is a way of canvassing for clinical ideas. Sessional GPs pitching ideas are more than welcome,' he said.