Findings from the poll, which received responses from about 50% of CCGs and 620 (5%) sessional GPs in England, were revealed at a GP magazine conference in London last week.
Speaking at the event for locum GPs, Dr Su Stone, clinical lead for the RCGP sessional GPs in commissioning project, said the survey showed that just 7% of sessional GPs felt their CCG held them in the same regard as partners.
Nearly all of the CCGs (95%) that took part said they allow GP partners to vote in elections, but just 65% allow locum or salaried GPs to vote.
Two thirds of CCGs felt sessional GPs were able to engage in all aspects of their work.
But the survey found that although 48% of CCGs said they communicate regularly with sessional GPs, only 37% of sessional GPs felt they were being kept informed.
Dr Stone said the survey had found a 'massive disparity' between different CCG areas. 'In some areas, locum and salaried GPs are CCG chairs, while in others they are not involved.'
However, she said she was surprised to find locum and salaried GPs were not always actively excluded, and 'apathy' was to blame for low levels of involvement in some areas.
Chief executive of the National Association of Sessional GPs Dr Richard Fieldhouse, who chaired the conference, said the results were disappointing but not surprising.
He argued that sessional GPs should be included in commissioning because they had no conflicts of interest and worked across multiple practices.
Full results of the survey are expected in June or July.