SYDNEY, Australia—American pop icon Britney Spears is "extremely upset" by media reports that disgruntled fans walked out of her first ever Australian concert because she was lip-synching, her promoter Paul Dainty said.

Dainty said the reports that concert-goers stormed out of Friday's show in Perth because it was lackluster and not performed live were "the biggest lie I've ever heard."

"I'm so angry," he told Monday's The Australian newspaper.

"We can take heat if there's something wrong and people can review shows badly—that's something you have to live with—but to say people stormed out of the show was an absolute fabrication."

Dainty said Spears, on her first major tour in five years after myriad personal problems, had been rattled by reports that some people left after just three songs.

"Britney is aware of all this and she's extremely upset by it," Dainty said. "She's a human being. I'm embarrassed, with such a big international entourage here with Britney, to be part of the Australian media when I see that kind of totally inaccurate reporting."

Management at Perth's Burswood Dome, where the first concert was held, said his office had received no complaints from the 17,000 people who attended the show during which Spears mimes to some of the songs.

"From Burswood's perspective, the event was a huge success," a spokesman said.

But one fan told the Nine Network: "People are paying for it and have come here, so she should sing."

Spears, 27, is performing 15 concerts in Australia, in Perth, Melbourne, Sydney, and Brisbane as part of the Circus tour which kicked off in New Orleans in March.

The extravaganza had earlier hit trouble as Australian fans voiced unhappiness it was not all sung live, with New South Wales state officials suggesting tickets should carry disclaimers.