More patients will be forced to wait for a week or more to see their family doctor because of a shortage of GPs.
Some 27 million patients in England will have to wait for at least a week for an appointment with their GP next year because of the shortfall, the Royal College of General Practitioners (RCGP) warned.
The college says numbers of GPs in England are in sharp decline compared with a rise in the the amount of hospital doctors - a gap which it predicts will widen.
Family doctors are concerned that waiting times will increase further, with 71% expecting them to be longer within the next two years because of fewer resources for general practice, the RCGP said.
Dr Maureen Baker, chairwoman of the RCGP, said: "It is vital to ensure that patients are able to access their local GP quickly and effectively - just as it is important for hospitals to have adequate numbers of qualified consultants to look after patients who are in need of acute health care.
"We need to ensure that we have enough GPs to provide patients with good access to high-quality health care in local communities across the UK."
The RCGP said that 11 years ago there were 2,500 more full-time equivalent GPs than hospital doctors.
Last year, there were 31,700 GPs compared to 38,200 hospital doctors, a difference of 6,500.
The RCGP expects that gap to widen further, with a predicted 37,000 GPs and 59,000 hospital doctors by 2022.
Last year 26.2 million people waited more than a week to see their GP, with a further 800,000 likely to face the same delay in 2014.
The declining proportion of GPs coincides with a dramatic slump in the proportion of the NHS budget spent on general practice, the RCGP said, which has dropped to its lowest share on record of 8.39%.
The only way to reverse the trend of lengthy waits is to increase the budget for general practice to 11% by 2017, starting with an increase of 1% of the NHS budget next year, it suggested.
Dr Baker said: "Most people want to be looked after in their local community and they want to be able to see their GP quickly. The dramatic diversion of doctor posts away from general practice into hospitals works against this fundamentally important principle.
"Ministers say repeatedly that we need to alleviate pressure on hospitals by delivering more care in the community, yet the numbers of posts being created for consultants and GPs is completely at odds with this.
"If waiting times get longer, it will be more difficult for GPs to ensure that problems are caught early, and the pressure on A&E will intensify. This is bad news for patients and bad news for the whole of the NHS."
Patricia Wilkie, chairwoman of the National Association for Patient Participation, said: "Patients greatly value being able to consult with and speak to their GP who is local, who knows the patient and their family and whom the patient trusts.
"Sadly very many patients are increasingly having to wait for one to two weeks and sometimes longer to see their GP...
"Unless there is an increase in the overall numbers of GPs and more financial resources to practices to employ more GPs to provide a safe and timely service, patients will have no alternative but to use A&E to receive the medical attention they need.
"This is not what patients wish nor the best use of NHS resources."