Results of the first survey of GPs since the national roll-out of NHS 111 emerged as NHS England warned failing providers they could face fines and contract cancellations.
More than 65% of GPs surveyed by LMCs in the north-east of England said their experience of the service was poor or very poor. Just 7% reported a good or very good experience.
Of those who worked in out-of-hours care, 83.3% said the service had become worse or much worse since the introduction of NHS 111.
Asked about the quality of clinical information supplied by the service, only 4.6% of GPs surveyed said it was clear and concise, against 88.5% who said it was not.
GPC negotiator Dr Peter Holden said the roll-out of NHS 111 had been 'outrageous and cavalier'. He said: 'It was without common sense and reckless. They have been dicing with patient safety, and we warned them.'
NHS England deputy chief executive Dame Barbara Hakin told a 3 May board meeting that CCGs in some areas had fined providers.
A 'couple of providers' had been responsible for 'seriously poor performance', she said, and NHS England would work with CCGs to impose financial penalties or revoke contracts if they failed to improve.
Dame Barbara said urgent reviews would examine the sustainability of NHS 111 and how contracts were awarded.
NHS England chief nursing officer Jane Cummings told the BBC the service had improved significantly across the vast majority of England, with 113,000 calls handled over the May Day weekend.
But questions have been raised over claims in Dame Barbara's report that there was no central mandate to integrate GP out-of-hours with 111.
Dr Holden said this was untrue, and Manchester LMC secretary Dr John Hughes said instructions to switch out-of-hours to 111 came via the former NHS North of England SHA cluster. 'Out-of-hours providers were told they had to make call handlers redundant and calls would be handled through 111,' he said.
Chief executive at Birmingham out-of-hours provider Badger, Dr Fay Wilson, said she had been told by the CCG that opted-out practices would all move to 111.