The medics are seeking 1.4 million yen ($9,000) in total damages from Google in a bid to hold the US tech titan accountable for inaction over the reviews.

They sued the company on Thursday, saying they are powerless to reply to, or refute, reputation-damaging reviews because of their obligation to patient confidentiality.

"People who post online can say anything anonymously, even if it's nothing but slander or verbal abuse", one of the participating doctors told reporters.

"It's like I'm a punching bag", he said under anonymity.

The case at Tokyo District Court is believed to be the first class-action lawsuit in Japan to target a platform over negative online reviews, a lawyer for the plaintiffs said.

"Despite the ease with which they are posted, it has become extremely difficult to get the reviews taken down," lawyer Yuichi Nakazawa told AFP.

"This can lead to doctors doing their job under the constant fear of receiving horrible reviews", he said.

The objective of many medical institutions is not to satisfy patients, but to deal with their illnesses from a professional standpoint, the plaintiffs' complaint said.

"Clinics that give patients only a perfunctory diagnosis and prescribe medicines as requested would be inappropriate medically, but highly appreciated by patients," it said.

The nature of the job can also sometimes leave doctors susceptible to ad hominem online attacks by patients holding a grudge, plaintiffs argued.

If the situation remains unaddressed, doctors "may find themselves hesitant to be firm and refuse medically unnecessary examinations or medicines requested by patients," Nakazawa warned.

That ultimately does society a disservice, he argued.

Google Maps is so widely used in Japan that it serves as "infrastructure" for daily life, according to the complaint.

So Google should be able to "easily recognise" the disadvantages to medical businesses if unfair reviews are left unaddressed, it said.

The plaintiffs acknowledged that Google takes down some Maps reviews under its own guidelines, but criteria for removal is opaque and "few" are deleted, they alleged.

Google told AFP it is "making efforts to reduce inaccurate and misleading content on Google Maps".

"With the combination of human operators and computers, we are protecting the profile of companies around the clock, and removing unjust reviews", the company said.