They demanded that alternative providers only be used where there was an identified need and existing providers had been given the option to deliver the service.
Dr George Rae, GPC member for Tyne and Wear, said alternative provision could alter radically the face of primary care.
The original remit of APMS was to add capacity in underdoctored areas, he said, but alternative providers were increasingly being brought in to run single-handed practices. It was the government introducing not constructive discomfort but destructive discomfort in primary care, Dr Rae said.
'We don't know the full scale of the government's plans,' he pointed out. 'We need to ensure that the profession says categorically that enough is enough.'
He pointed to a case in Sunderland where a PCT-employed doctor had turned round a deprived, poorly performing inner-city practice, making it a training practice - only to see it put out to competitive tender.
'Surely that is unacceptable,' he said. The PCT was trying to advance the 'pluralistic ideological agenda of the government'.
'The profession is looking to the GPC for leadership, advice and help,' Dr Rae said.
Delegates voted unanimously that alternative providers should only be used where a need was identified, where existing providers had been given the chance to deliver the service, where the bidding process and access to funding were equitable and where there was a right of appeal.
A motion that future providers be required to meet the same quality standards as current providers was also carried.
Last week a bid to stop North Eastern Derbyshire PCT awarding a contract to run two GP surgeries to UnitedHealth Europe was lost. A judicial review examined whether the PCT had failed to properly consult residents.