Telstra loses court battle against Optus

Telstra's claim its rival Optus engaged in misleading or deceptive conduct has been dismissed by the Victorian Supreme Court.

It comes after Telstra won an interlocutory injunction to stop Optus running advertising with the phrase "empires end", after arguing the ad wrongfully implied Optus "undisputedly" operated Australia's best mobile network.

But Justice Ross Robson on Wednesday ruled Telstra had failed to establish its rival engaged in misleading or deceptive conduct.

"The representation that Optus' network is undisputedly better than Telstra's is not conveyed by the advertisement," he said in his judgment.

He dissolved the injunction granted earlier in May and ordered that Telstra pay Optus' legal costs.

Earlier in court, Optus said its "empires end" slogan was a wry reference to history and technological change, and described Telstra's analysis as an "artful construction" without reason.