Melbourne gangland lawyer Zarah Garde-Wilson is suing technology behemoth Google in a bid to unmask an online reviewer who she suspects is actually a legal competitor.

Key points: Ms Garde-Wilson said her law firm had never represented anyone with the reviewer's account name

Ms Garde-Wilson said her law firm had never represented anyone with the reviewer's account name The court action is aimed at forcing Google to turn over the user's identifying information

The court action is aimed at forcing Google to turn over the user's identifying information Her lawyer, Mark Stanarevic, recently secured a Federal Court order for Google to reveal the identity of an anonymous user in a similar case

The lawsuit, which was filed in the Federal Court on Monday, paves the way for defamation action against the author.

The offending review was written under the name Mohamed Ahmed about two weeks ago and criticised Ms Garde-Wilson's law firm, Garde Wilson Criminal Lawyers.

Ms Garde-Wilson responded shortly after the review was posted.

"My practice has never acted for a Mohamed Ahmed and we have forwarded this review to the Google investigations team to be removed," she wrote publicly.

But despite requesting the Google review be removed, it stayed on her page.

It has since disappeared after the lawsuit was filed.

Google has been forced to reveal the identity of another anonymous reviewer in a similar court case. ( ABC News: Ben Sveen )

Ms Garde-Wilson is being represented by Mark Stanarevic, of Matrix Legal, who recently succeeded in convincing a Federal Court judge to order Google to unmask the identity of an anonymous reviewer who allegedly defamed another client, Melbourne dentist Matthew Kabbabe.

The order, by Justice Bernard Murphy, compels Google to turn over identifying information including any names, phone numbers, IP addresses and location metadata.

The technology giant has also been ordered to provide any other Google accounts, including full name and email addresses, which may have originated from the same IP address during the same period of time.

Ordinarily, serving an international company like Google would take several months because, under an international treaty known as the Hague Service Convention, the documents would first have to be lodged and processed in two countries.

But Mr Stanarevic has found a legal loophole which allows Google to be served directly by international registered post.

Mr Stanarevic said he had dozens of business owners express interest in joining a class action against Google, and was currently in the process of developing a statement of claim.

He said Google had a duty of care to small business owners and criticised the technology giant's failure to remove defamatory reviews from a platform it monetises.

He described Ms Garde-Wilson, who represented convicted drug lord Tony Mokbel and slain gangster Carl Williams at the height of Melbourne's bloody underworld war, as a "hard-working lawyer and mother and business owner".

"It is upsetting she has to go through this process as well, like many other small business owners in Australia," Mr Stanarevic said.

"Google keeps earning millions a week in AdWords from the Australian public."

Google declined to comment.