The heat is on Down Under. The Australian government is stepping into a lip-synching scandal erupting over portions of Britney Spears’ Perth concert tour. The Minister for Fair Trading is demanding a disclaimer, which states that part of the show is pre-recorded, be placed on all tickets sold to see Britney.

Britney performed to over 17,000 fans at the Perth Burswood Dome last night, but thousands of disgruntled fans — some having paid up to $1,500 per ticket — reportedly stormed out of the Australian debut of The Circus concert, infuriated by the pop singer’s “appalling” performance on stage.

“It was just really bad,’’ Kathy Wright,32, told the Sydney Herald on Friday. “We are really big Britney fans but it was crap,” her friend Josh Blee piped in.

“I thought after the music awards she would make up for it with a wicked concert, but she has let us down,” he said.

Other fans complain they could barely see the show from their seats.

“She is a little dot on the stage,’’ says Maria Camody, who was disappointed that the giant screens peppered throughout the arena did not show any vision of Spears performing.