A survey of 233 locum and salaried GPs by the National Association of Sessional GPs (NASGP) found just 24% had been contacted by their PCT or a consortium.
More than two thirds (67%) had received no information at all and 9% had been kept informed of local developments by colleagues.
Last month, NASGP chairman Dr Richard Fieldhouse warned that consortia were failing to engage sessional GPs through 'sheer ignorance' or because they have no means of contacting them directly.
One GP in East Sussex, responding to the survey, said he had not been invited to discussions and 'will not be able to vote in the system the partners are planning to run'.
Another respondent, a GP locum in Cumbria, said partners in his practice 'stated that principals are the ones to carry the financial risk, so it was felt there was no point in involving sessional GPs'.
Dr Fieldhouse called for a comprehensive database of sessional GPs so that PCTs and consortia can contact them.
Another respondent, a GP in London, said his PCT did not communicate in any way with sessional GPs. 'Only because I used to be a principal and remain on the LMC's email forum do I find out anything at all about what's going on.'
The BMA says sessional GPs are well placed to take up roles in consortia because working across multiple practices gives them a 'unique understanding' of local patients.
Dr Fieldhouse was keen to stress that in spite of the survey's results there are good examples of consortia encouraging sessionals to join consortia or contribute ideas.