GPs in Oxfordshire are warning that a dispute over surgery opening hours could end with them severing ties to the NHS.

They say they may follow the example set by dentists and offer patients treatment privately instead. And they claim a planned GP super-surgery for the county would be the first step to privatising primary health care.

Almost 200 doctors met last week to discuss health ministers' plans to extend surgery opening hours without any extra funding.

Dr Prit Buttar, of Abingdon Surgery, in Stert Street, said: "Many say the time is coming when we will have to do as the dentists have done.

"Nobody likes the thought of that, but if it gets to the stage where clinical freedom is being dictated to by political targets, then maybe our contract needs to be between us and our patients, and not with a state that wants to tell us what to do on the basis of a political whim."

The Government clashed with doctors' leaders yesterday over negotiations to extend surgery opening hours, insisting it was not unreasonable for patients to expect to get appointments with their GPs in the evening and at weekends.

Health Secretary Alan Johnson has written to every GP in England to explain why he wants surgeries to open longer. He says surveys of patients show there is a demand for extra surgery hours.

Dr Buttar said the Government's plan would leave his practice out of pocket by £10,000 a year.

He said: "If patients want an 8am-8pm surgery I'm happy to arrange it, but people have to realise it costs a lot of money and will be done at the expense of other things, which is an expensive move just to please a few people who say they would like extra hours.

"The only way I can do it is by reducing hours elsewhere, affecting patients during the day, who would be forced to see us after hours instead."

Doctors are also angry about a Government plan to install a private GP provider in every Primary Care Trust area, to run a surgery open from 8am to 8pm, seven days a week. An £800,000 contract would be on offer in Oxfordshire.

Dr Rickman Godlee, a GP at the Church Street Practice, which serves Wantage and Grove, is the chairman of the Local Medical Committee, which represents GPs.

He said: "Although we're already very well provided for, our PCT will have to do this and encourage 6,000 patients to move from their current GPs to register with it.

"My view is that this money would be better spent elsewhere and I'm concerned existing GP practices may find themselves up against unnecessary competition.

"This is the first stage to privatising primary care."

The idea has even been criticised by members of Oxfordshire PCT.

The trust's clinical executive committee chairman, Dr Stephen Richards, said: "The issue goes much deeper than being about a few extra hours' work, and GPs have some reason to be concerned.

"Bringing in the private sector could be the first major step towards privatising GP care."