The majority of family doctors are concerned that they will not be able to properly care for vulnerable older patients because they are struggling to cope with "spiralling workloads and dwindling resources", leading doctors said.
More than four in five GPs are worried that it will become increasingly difficult to deliver continuity of care to at-risk elderly people, according to a poll conducted by the Royal College of General Practitioners (RCGP).
The college warned that if general practice "starts to crumble" there could be "disastrous" consequences for patients.
The poll of 206 GPs also found that 70% were concerned that patients could face longer waiting times.
Four in five said they had "insufficient resources" to provide high quality patient care and 47% admitted they had cut back on the range of services they provide for patients.
The RCGP said general practice was at "breaking point" and called on officials to create an emergency package of additional investment for general practice - like the £500 million bailout given to A&E departments last week.
Clare Gerada, chairwoman of the RCGP, said: "The results of our survey paint a bleak picture for patients, the profession and the future of general practice. GPs are grappling with a double whammy of spiralling workloads and dwindling resources, and big cracks are now starting to appear in the care and services that we can deliver for our patients.
"We are particularly concerned about the effect this is having, and will continue to have, on waiting times for GP appointments. We fully understand that patients are already frustrated - and GPs are doing their best to improve access to appointments - but the profession is now at breaking point and we do not have the capacity to take on any more work without the extra funding and resources to back it up.
"GPs currently make 90% of patient contacts for only 9% of the NHS budget in England. Some GPs are making up to 60 patient contacts in a single day, which is not safe, for patients or GPs.
"We are working our hardest to make sure that patients are not affected but the status quo is no longer an option. We must have an emergency package of additional investment for general practice to protect GP services and protect our patients from even deeper cuts to their care and longer waiting times."