A majority of GPs say they will not provide abortion pills to women in the first 12 weeks of pregnancy if it becomes law, according to a survey of family doctors.
Nearly seven in 10 of the 497 GPs who voted in a closed doctors' forum said they would not be involved in medical abortions.
Around 15.7pc said they would provide the service and 16.1pc were "unsure".
The doctors are among 3,700 GPs who are registered with GPBuddy.ie, the online medical directory designed by GPs for Irish healthcare professionals.
They responded to a series of questions on the confidential forum.
Although the survey has its limitations, it indicates that, if rolled out nationwide, it would mean a substantial number of GPs would opt out of the abortion service.
However, they would be obliged to refer a woman seeking an abortion to a doctor who provides the procedure.
Asked how they would vote in the upcoming referendum, 58.5pc of the 518 GPs who responded said they supported the repeal of the Eighth Amendment. Another 25.3pc said they would vote to retain it and 14.5pc were unsure.
A third question was posed asking if they thought GPs should be designated as the medics to provide medical abortions - as proposed in upcoming draft legislation.
There is considerable opposition from GPs to be chosen as providers. Some three-quarters of 493 who responded said they disagreed with delegating this to GPs.
Another 12.5pc were unsure but more than one in 10 supported the proposal.
Dr Conor McGrane, a GP in north Dublin who was involved in the survey, said no GPs trained in Ireland or the UK received direct tuition on providing medical abortions.
He said the doctors who said they would not become involved were likely to be influenced by having no training or lack of time due to their busy practices.
"In the UK, a woman sees her GP but she is then referred for a medical abortion to an NHS clinic," he said.
Under proposals by the Government, GPs in regular practice here would be among the minority in Europe to provide the service directly, he added.
Currently, GPs are confined to providing information on abortion to patients but they cannot make a referral to a clinic abroad.
He said the 15pc who say they would provide the service would tend to be quite keen to do so and may be already involved in women's health services. "You could have dedicated clinics within practices," said Dr McGrane.
There are 2,600 GPs involved in the HSE's medical card scheme.
Under the proposals, a woman who has a medical abortion under 12 weeks would take two medications, usually 24 to 48 hours apart, to induce a miscarriage.
It is envisaged there would be a gap of between 48-72 hours between a woman's first GP visit and taking of the pills, to allow reflection.
Dr McGrane said in the vast majority of cases the abortion proceeds without complication.
But if something does go wrong, a woman can suffer heavy bleeding, which would require treatment.
GPs are likely to have to pay higher insurance premiums if they are providing medical abortions, he added.