The Irish College of General Practitioners (ICGP) has said the extension of free GP care to an additional 400,000 patients in Budget 2023 could lead to more than 640,000 extra consultations every year.
It said that most GP practices in both urban and rural Ireland are unable to take on new patients, against a "growing workforce and workload crisis".
The group is calling for the Minister for Health to set up a working group as "a matter of urgency" if this extension is to proceed.
A 2021 survey of its members found that almost three quarters (74%) of GPs could not take any new private patients, while almost eight in ten (79%) could not take any new medical card patients.
The ICGP is hosting its autumn conference in Dublin today, where a discussion paper on "the workforce and workload crisis" is being launched.
The paper includes ten proposed solutions to the challenges facing the sector.
These include a proposal to double the number of GP practice nurses, an expansion of GP led multi-disciplinary teams, a fast tracking process for suitably qualified GPs from outside the EU, providing suitable premises, an incentive scheme to attract GPs to rural Ireland and increased exposure to general practice in medical schools.
The Department of Health said the Government has committed to "significant additional resources" for the GP sector, which it said would make it more sustainable and increase GP numbers.
"The additional resources provided include increased capitation fees for GPs, supports for practices in rural areas and in urban areas of deprivation, and the allocation of resources to implement the Chronic Disease Management programme," the statement said.
The department said that it and the HSE have commenced "preparatory work on a strategic review of general practice under the 2019 agreement with GPs", which will examine a broad range of issues and set out measures to deliver sustainable general practice.
"It is anticipated that the ICGP will provide an important input into the review. The ICGP has made and will continue to make a vital contribution to the delivery of general practice in this country," it said.
While the ICGP welcomed this review, Professor Tom O'Dowd urged the Minister for Health to set up a working group "as a matter of urgency, if the extension of free GP care is to proceed".
There are currently 4,257 doctors working in general practice.
While the number of new trainees coming through the system has increased in recent years, a quarter of existing GPs are aged over 60 and due to retire in the coming years.
The ICGP said that practices are busier than ever, but are less able to find replacements for retiring GPs, or new GPs to expand growing practices.
Dr Sinéad Cronin - a Drumcondra native who took over a 40-year-old GP practice in the area with her husband 18 months ago - is looking after around 4,000 patients.
However, the practice is now starting to show the symptoms of a system-wide illness - a shortage of GPs.
"We turn away between five and ten new patients who are requesting to join the practice here every day. That's something we don't like to do, we want to be able to look after everybody, but we just physically can't," she said.
The practice is also currently looking after a small number of patients who have moved out of Dublin but have not been able to get a new GP in the rural areas they are now living in.
"We're in a position where we have to still provide care to these patients until they find a new GP, which we are happy to do, but its not ideal from a patient safety perspective, and it also means that we can't take patients living in the local area, which is what general practice is all about."
Dr Cronin said she is finding it difficult to get other doctors to help with the workload, and had just one application to join the practice when she goes on maternity leave at Christmas.
She said it is difficult for young doctors to get into general practice because there is a big financial burden and very little assistance in taking over a practice.
