The Federal Court of Australia has banned Telstra from re-running the "unlimited" advertisements for a period of three years.
Optus Mobile took Telstra to court in May claiming that the advertisement was likely to mislead consumers.
In May, Justice Gleeson found that Telstra's advertisement on its homepage and billboards in metropolitan areas which claimed - "One word from Australia’s best mobile network. Unlimited" - falsely conveyed the representation that the provider offers a mobile product or service that is unlimited.
Now, the court has restrained Telstra from publishing, broadcasting, communicating and/or otherwise distributing; and causing the publication, broadcast, communication and/or distribution of, the advertisements for three years.
During the proceedings Optus alleged that the use of the word "unlimited" by Telstra could imply that Telstra offers no limitations on the speed at which data can be downloaded.
Furthermore, other implications centre around the volume of data that can be downloaded at unrestricted speeds, in addition to the user’s ability to download data without interruption or delay, and the type of mobile device on which the product or service can be used.
Optus also alleged that the advertisement suggested Telstra has a mobile network that provides unlimited geographical coverage throughout Australia, wherever the user is located.
Telstra denied the allegations during the hearing on 23 May, disputing that the word “unlimited” in the context of the surrounding words and imagery in the advertisements conveyed “nothing definitive, doing no more than to cause a viewer to wonder about its meaning”.
"We will comply with the Federal Court decision, which applies to only a small part of our overall advertising and promotional material for our mobile data plans," a Telstra spokesperson told ARN at the time. "We will carefully consider the judgment before deciding our next steps."
An Optus spokesperson told ARN that it took the action against Telstra because it felt the advertisement was likely to mislead consumers.
"Our action has been comprehensively vindicated by the judgement and the offending advertisements have been removed from the market. Optus welcomes the closure of this successful action.
ARN has sought further comments from Telstra.