Operation Richmond, launched by the Independent Broad-based Anti-corruption Commission in 2019, investigated the Victorian government's negotiations with the United Firefighters Union.
They centred around reforms to merge Metropolitan Fire Brigade members and career Country Fire Authority firefighters into the new Fire Rescue Victoria.
IBAC commissioner Victoria Elliott indicated the final report would be released to the public by July 1 but that plan has been sidetracked by a Victorian Supreme Court injunction application.
The identity of the person who lodged the application remains secret after barrister Nick Wood SC sought for his client's name to be restricted.
The applicant was seeking to stop the report from being transmitted to parliament and any publication of their name would render their application useless, Mr Wood said on Friday.
The grounds for the application were not aired in open court and Mr Wood also sought for the entire court file to be closed, meaning media could not access any of the documents filed.
Mr Wood pushed for the restrictions and a pseudonym order over his client's identity, which was opposed by media barrister Justin Quill.
Mr Quill argued the parts of the IBAC report that were being disputed could be suppressed but the applicant's identity should not be.
"It is hard to imagine a matter in this court that has a greater public interest," he told the court.
"This court is being asked to restrict the flow of information to our parliament. That is an extraordinary thing Your Honour is being asked to do."
Mr Quill also argued a restriction on the applicant's name would lead to speculation and innuendo.
"There will be nothing stopping the reporting of, it could be person X or it could be person Y," Mr Quill said.
"That could occur and that is absolutely not in the public interest."
IBAC also opposed the pseudonym order but the watchdog's submissions were heard in closed court without media present.
IBAC's barrister Frances Gordon KC did give an undertaking in open court, promising the corruption watchdog would not publish the report while the case was before the courts.
Justice Claire Harris is due to decide on the pseudonym orders later on Friday.
There were reports Daniel Andrews, who was Victorian premier at the time of the firefighter reform negotiations, was questioned over Operation Richmond but he refused to confirm or deny that was the case.
Victorian Premier Jacinta Allan on Friday bristled at suggestions the delay in the report's publication was conveniently timed, with a state election six months away.
"The government is not a party to this matter and has no involvement in these proceedings," she told reporters in Bendigo.
"That claim of that nature undermines the work of IBAC."
Shadow Attorney-General James Newbury accused Labor of orchestrating the delay without offering any proof.
"This government, this Labor movement, doesn't want their dirty linen aired publicly so there's no wonder they're doing everything they can to cover it up," he said.
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