Doctors are powerless to act as their professional reputations are ruined on Google reviews that appear whenever someone searches their practice online, AMA NSW says.

The branch says it is lobbying the tech giant to allow doctors to disable its review feature, arguing practices are being harmed by malicious comments.

Google allows anyone with an account to rate a business out of five and make comments on their experience, which appear online without any moderation.

In June, a plastic surgeon from Sydney, Dr Kourosh Tavakoli, was awarded $530,000 in damages in the Supreme Court of NSW, after suing a patient for defamation for a Google review claiming he had acted improperly and incompetently.