Almost two-thirds of doctors entered on the medical register for the first time last year had qualified outside of Ireland, it has emerged.
Of the 2,190 doctors registered for the first time on the Medical Council's register last year, only 35% held an Irish qualification.
By the end of last year, there were 23,007 doctors on the register and 58% were Irish medical graduates.
The Medical Council is concerned that an increasing number of doctors with a right to practise in Ireland are choosing to leave the register.
The regulatory body's latest Workforce Intelligence Report found that 2,830 doctors withdrew voluntarily from the register between 2015 and 2017.
Irish doctors with basic medical qualifications accounted for 42% of all the withdrawals, with most planning to practice in Australia, Britain, Canada, New Zealand and the US
Doctors said they are moving abroad to do a fellowship, support a partner undertaking a fellowship or to further their career. Financial reasons were given for not maintaining dual membership of medical regulatory organisations when working abroad and maternity leave was also reported.
Of the 2,830 voluntary withdrawals recorded 1,846 practitioners (65%) set out their reasons for doing so. More than a third (37%) left to move to Britain to practice medicine, while almost in five (19%) went to Australia and over a quarter (27%) to another jurisdiction.
Some doctors said they are expected to carry out too many non-core tasks when they work in Ireland and there is a lack of employer support and respect by senior colleagues.
Doctors complained of workplace understaffing and issues relating to the European Working Time Directive and the hours they are expected to work.
Medical Council chief executive, Bill Prasifka, said their survey shows that doctors trained in Ireland do not want to work in the Irish health service.
"As a result, the percentage of foreign qualified doctors on the register is increasing. They are, if you will, filling the gap,” he said.
President of the Medical Council, Dr Rita Doyle, said the situation is leading to an over-reliance on overseas trained doctors, which is escalating.
"The cultural challenges within the Irish health system, which are highlighted in the report, also need to be addressed in tandem with an increase of health practitioner supply. Otherwise, retention will remain a growing issue," said Dr Doyle.
The Irish Medical Organisation said Irish qualified doctors are emigrating in droves but, alarmingly, the report confirmed that doctors from other countries are leaving too because they do not like working in Ireland.
The Irish Hospital Consultants Association said the report confirms that much-needed consultants are being driven abroad and pointed to the failure to fill 487 hospital vacancies in the public health service.
The National Association of General Practitioners said the report provides evidence of what they are seeing on the ground - doctors are going to countries where they feel valued and can achieve their full potential.