High-level moves are under way to end an EU directive which prevents a medical watchdog from subjecting more than 1,000 doctors to an English language test.
The doctors, from non-English speaking EU countries, have been allowed to register here without undergoing a test to determine their proficiency in English.
It is illegal for the Medical Council to subject a medic trained in any of the EU member states to an English language test.
The Irish Independent has learned that this section of the free-movement directive is causing increasing concern because of the potential knock-on effects for patient safety.
The EU-trained medics are free to apply to work here without proving how fluent they are in English.
But a spokewoman for the Medical Council confirmed it was seeking to have the law changed to allow language vetting to take place.
In 2011, the council received 33 complaints about doctors failing to communicate, and some being rude.
One of the most high-profile cases involved Romanian-trained medic Asia Ndaga (31), who was a senior house officer at Letterkenny Hospital in Donegal.
It emerged she was unable to take a pulse and had difficulty communicating because of her poor English.
A spokeswoman for the Medical Council said: "There are approximately 1,800 doctors registered to practise in Ireland who qualified within the EU, out of a total of approximately 18,000.
"Excluding UK nationals, approximately 1,100 doctors qualified elsewhere in the EU and would account for approximately 6pc of all registered doctors.
She added: "For many years now the Medical Council has highlighted its concern at its inability to assess the English language competence of doctors coming to work in Ireland from within the EU.
"In the interests of patient safety, doctors must be able communicate in the language of the country in which they are seeking registration.
"It's important to note that the EU Professional Qualifications Directive is currently in the process of being modernised."
Doctors who put patients at risk can only be removed from the medical register after incidents are uncovered and they appear before a fitness-to-practise hearing.
The doctors are free to apply to work in hospitals and although some employers apply language tests, they are not mandatory.
The British government has also said it will try to close the loophole. In one case in Cambridgeshire, a German-trained GP gave a lethal dose of a drug to an elderly man. It later emerged he had problems communicating in English.