Dr Ron Singer, president of the Medical Practitioners' Union (MPU), said the petition will send a strong message to government that GPs still have ‘grave concerns’ about the amended Health Bill.
He said the government must not claim that GPs’ participation in clinical commissioning groups means they are supportive of the Health Bill.
Dr Singer said: ‘We all know that many GPs have signed up to clinical commissioning groups in order to 'keep up' with proposed changes and to protect our patients' interests.
‘By challenging the government's argument that GP's involvement in commissioning equals support, we can really make a difference in challenging the Bill.’
The MPU, meanwhile, said it supports calls for the Health Bill to be scrapped. But it said if it is not withdrawn the government must allow ‘full and proper’ scrutiny of the amended Bill.
It warned that getting the Bill wrong coupled with the £20bn efficiency savings will put more lives at risk.
It said: ‘Adequate scrutiny of this complex Bill and its large number of equally complex amendments is not possible on the current timetable.
‘We further demand that, on such a vital aspect of public policy, there should be no use of the 'guillotine' to curtail debate.'