The Star casino in Pyrmont and a prominent Sydney restaurateur are locked in an escalating dispute over use of a signature "golden star" symbol which threatens to boil over into the federal court.

Peter Petroulas, the managing director of GPO Grand restaurants in Martin Place and Balmoral Beach, accuses the Star Entertainment Group of infringing his copyright on branding he has used since 2002.

Mr Petroulas claims the matter dates back to 2009 when he was asked to a meeting with then Star casino chief executive Larry Mullin, managing director Sid Vaikunta and head of hospitality Victor Tiffany.

The executives were embarking on a redevelopment that included high-end restaurants and Mr Petroulas says he walked them through his strategy during a five-hour meeting at his Martin Place headquarters in the historic GPO building.

The executives subsequently left the Star, most notably Mr Vaikunta, who spectacularly resigned over a sexual harassment scandal.

But in a rebranding exercise, in November 2015 the Star unveiled its current logo, a gold star featuring what may or may not be an "S", which Mr Petroulas believes is so similar to the one he has used for more than a decade that it infringes his copyright.

Mr Petroulas says he was not aware of a concurrent application to trademark the gold star logo until after it was registered and the objection period had expired the following May.

He says this was because the application was made by a lawyer with King & Wood Mallesons, a firm engaged by the casino group.

The rights were later transferred to The Star by the lawyer. Mr Petroulas argues the process is a breach of the trademark act which says a logo can only be registered by its owner.

What precisely constitutes an "S" is also in dispute after the Star objected to an application by Mr Petroulas to register two new gold star logos featuring the letter.

This was done to brand his Greek restaurant Subterranean Bar and Grill and Japanese eatery Sosumi Sushi Train.

"By definition a symbol can only be defined as the letter "S" when the ends of the letter curl back into the spine of the letter," he asserts in a submission to IP Australia, which manages trade mark issues, defending his applications.

"I note that by definition the squiggle in the centre of the Casino Device is not the letter 'S'. ".

In March, Mr Petroulas wrote a letter of demand to the Star's board which called on the company "cease and desist" from using the gold star logo, destroy all copies of it and remove it from its premises in Sydney and Brisbane.

He says he will take The Star to the federal court.

"In my opinion it's a clear breach of my rights to actually see the application going through and be able to object to it," he says. "They've denied me that opportunity."

But a spokesman for The Star labelled Mr Petroulas' claims "spurious and insulting".

"The Star Entertainment Group proudly embraces the highest professional standards," he said.

"We trademarked our logo after following the registration process to the letter."

"There were opportunities for objections to be lodged and that did not occur. Now we seek to protect the brand equity in the logo and the brand we've developed."