Radical government plans to rid the NHS of "problem" GPs could pave the way for a wholesale privatisation, senior doctors warned yesterday.

Health Department proposals to force "underperforming" GPs into short-term contracts were criticised last night by angry doctors' leaders. They fear it will make it easier for local primary care trusts (PCTs) to sack doctors and bring in private companies to run surgeries. They claim uncertainty caused by such a proposal might deter doctors from investing in patient services and could damage GPs' relationships with patients.

"The British Medical Association [BMA] is worried this is a step closer to privatising the health service," said Dr Laurence Buckman, chair of the BMA's general practitioners' committee. "The relationship between doctor and patient could evaporate as a result," he added.

Most surgeries currently have a "contract for life" which, critics argue, makes it almost impossible to deal with repeated poor performers as trusts can use a "carrot" but have no "stick".

Dr Buckman said: "It is an outrageous slur on most GPs to suggest a link between poor practice and breaking up the whole system of GP services. There are plenty of ways to deal with the minority of underperforming practices that don't include breaking up the continuity of care or flogging off GP practices to the private sector."

According to the Royal College of General Practitioners (RCGP), short-term contracts are a "red herring" as PCTs' existing powers are sufficient to tackle GP underperformance, if used effectively. They would prefer the introduction of minimum standards, if the standards are set by doctors but enforced by the trusts.

Professor Steve Field, chairman of the RCGP, said: "We do believe there is a need to ensure high-quality care is delivered to our patients. However, PCTs should not shrink away from their responsibility of helping practices to improve and, where necessary, ensuring the small percentage of underperforming practices do not continue."

The Department of Health refused to confirm it had plans to change the current system.