The new guidance is in draft form and open to public consultation, but the regulator has said doctors have a public protection duty to inform authorities if a patient is driving against medical advice.
Patient consent is not required for doctors to inform the DVLA if a patient has continued driving.
However, this new, stronger advice is part of a public consultation on the GMC’s core guidance on confidentiality, which aims to help doctors balance their legal and ethical duties of confidentiality with wider public protection responsibilities.
The guidance says doctors must disclose information - which can include risks of violent crime, serious communicable diseases, or risks posed by patients who are not fit to drive - which could help protect the public.
GMC chief executive Niall Dickson said: “Doctors often find themselves in challenging situations.
“This is difficult territory - most patients will do the sensible thing but the truth is that a few will not and may not have the insight to realise that they are a risk to others behind the wheel of a car.
“A confidential medical service is a public good and trust is an essential part of the doctor-patient relationship.
“But confidentiality is not absolute and doctors can play an important part in keeping the wider public safe if a patient is not safe to drive.
“We are clear that doctors carrying out their duty will not face any sanction - and this new guidance makes clear that we will support those who are faced with these difficult decisions.”
RAC Foundation director Steve Gooding said: “Thirty-seven million drivers depend on the car for getting about and for those with serious medical conditions there is a real fear around losing their licence.
“But with the right treatment, many illnesses will not lead to people having to hang up the keys.
“The worst thing motorists can do is ignore medical advice. If they don’t tell the DVLA about something that impacts on their ability to drive safely, then their GP will.”
The news comes at a time when the Fatal Accident Inquiry into last December’s Glasgow bin lorry crash has heard claims that driver Harry Clarke broke the “bond of trust” between patient and doctor when he failed to give full details about a previous blackout.
Clarke passed out in April 2010 when working for First Bus, but told his GP that he fainted in a hot canteen. In December 2014 he was at the wheel of a refuse truck which crashed in Glasgow city centre, killing six people.