Singapore Telecommunications’s Australian unit, previously ruled to have misled customers with its data-service advertisements, lost a bid in Sydney federal court to stop Vodafone Group Plc. from publicising its “infinite” mobile-phone plans.

Australia Federal Court Judge John Nicholas today denied SingTel Optus Pty Ltd.’s request for a temporary injunction barring Vodafone from advertising the plans, which offer unmetered calls to fixed-line and mobile-phone numbers for A$45 ($59) a month.

Optus claims Vodafone’s advertising campaign is misleading because it doesn’t sufficiently disclose that customers can’t make unlimited calls to satellite phones, voice mail, 1-800 numbers and directory assistance, according to court documents.

“I have serious doubts as to whether the ordinary and reasonable consumer would understand either of the television commercials as representing that the respondent’s plan allows a user to make an unlimited number of calls of any type,” Nicholas wrote in his judgment.

The Australian Competition and Consumer Commission previously sued SingTel Optus and won an order forcing the company to run corrective ads and pay fines. Federal Court Judge Nye Perram ruled in October that advertisements for Optus’s broadband service promised data services that customers weren’t likely to receive.