Analysis from Monash University found that in 2023, Victorian courts accounted for 521 of the 1113 suppression orders issued across Australia, a figure that surpassed all the other states and territories.
The report found public interest journalism had reached a "crisis point", highlighting how "severe" systemic barriers are preventing journalists from holding powerful institutions and individuals to account.
"Based on the review of previous studies and the interviews in this project, we conclude that public interest journalism in Victoria is at a crisis point," authors Alicia McMillan and Johan Lidberg wrote.
However, Supreme Court Chief Justice Richard Niall dismissed claims made in the report, adding the court system was committed to working with all journalists to ensure transparency.
"It contains a number of misleading claims, selective citations and suppression order data which has been debunked as incomplete and misleading,'" Justice Niall said.
All 12 senior journalists interviewed for the study, commissioned by the Melbourne Press Club, said courts routinely breached the Open Courts Act "with impunity".
"If the courts in Victoria continue down the path of increased secrecy, they risk losing the trust of the public and jeopardising the concept of natural justice," the report said.
While conceding the study was limited because no chief judges in Victoria's main courts agreed to be interviewed, the authors said the act had "largely failed" to improve open justice since its introduction in 2013.
Suppression orders can be applied for by defence and prosecution lawyers in all courts including magistrates, supreme and county, and can cover an accused's name, their victim's identity, details of the case, criminal history, charges, or a plea of guilty or not guilty.
In one high-profile instance, the media was prevented from identifying Tom Silvagni, son of AFL champion Stephen, for 18 months after he was charged with the assault of a woman.
Silvagni was found guilty of two counts of rape on December 5 but the suppression order was not lifted until December 10, with the case sparking community outrage.
Attorney-General Sonya Kilkenny would not commit to initiating a review of the Open Courts Act.
The data within the report was "at best questionable" as jurisdictions reported the issuing of suppression orders differently, she said.
Shadow Attorney-General James Newbury described the figures as "stark" and suggested suppression orders were being "misused".
Justice Richard Niall said the report's claims were not presented to the courts before publication.
The study's 10 recommendations included a review of aspects of the Open Courts Act, allowing accredited journalists to record court proceedings by default, and freedom of information reforms.