Health secretary Andy Burnham announced last week that patients will be able to register with any GP practice by autumn 2010. The move is aimed at increasing choice and allowing patients to register with GPs near their place of work.
'It means a patient's practice is based on their own needs and not on lines drawn on a map,' said Mr Burnham.
Shadow health secretary Andrew Lansley said the Conservatives announced similar plans two years ago. A spokesman for the party also ruled out dual registration.
But GPC chairman Dr Laurence Buckman said dual registration could solve problems that have stopped boundaries being abolished in the past.
'Dual registration is the obvious solution but it is very expensive because both practices have to be funded,' he said.
Dr Buckman said he had not been consulted about the DoH plans. As well as a 'long list' of administrative problems, Dr Buckman warned that social services may not visit vulnerable families registered remotely.
'Who visits people registered elsewhere? We are talking about services that are "sectorised" by PCT like district nurses, physio, and social services.'
He said it would be tough to decide how PCTs pay for patients registered outside their area. 'It's certainly not a hot topic. We have tried to make it work both as dual registration and boundary-less practice, and it has floundered.'
There was also a danger of practices in popular areas being overloaded with patients, which could undermine access and quality, said Dr Buckman. 'You could solve these issues in a better financial situation,' he said.