In response to a European Commission (EC) consultation on medical qualifications, the GMC called for powers to language test doctors at the point of registration.
Calls for language tests have gathered momentum since German locum Dr Daniel Ubani killed a patient in 2008 by accidentally administering an overdose of diamorphine.
The GMC also warned that the lack of consistency in European medical qualifications meant regulators could not accurately judge the quality of doctors.
It said European language testing rules were insufficient to ensure public safety.
'European Economic Area (EEA) applicants to the GMC register do not need to pass a language assessment even in cases where there is doubt,' the GMC response said.
'We have examples of EEA doctors seeking recognition and registration with the GMC who are not able to communicate in English and were assisted by an interpreter.'
The GMC called on the EC to allow it to test doctors' language skills 'in a proportionate manner' as part of the registration process. Inconsistent training standards across Europe were also a major concern, the GMC said.
'Comparability is largely based on the length of training rather than the training content or the range of competencies that medical education develops,' it said. 'The overall result is that competent authorities cannot have full confidence in each other's medical training.'
The GMC response said there was an 'urgent' need to audit medical qualifications across Europe and said discussions must start around minimum EEA training requirements.
But the GMC said EC plans for a Europe-wide curriculum must be considered carefully.
'There would need to be clear mechanisms, with legal status, to ensure European curricula are developed appropriately and updated regularly,' it said.