AceShowbiz - Whitney Houston has suffered another setback in her ongoing tour of Australia - fans allegedly walked out of her show in Sydney on Wednesday night, February 24 after the singer's voice began to fail. The "I Will Always Love You" hitmaker was previously accused of putting on a lackluster performance in Brisbane on Monday, February 22, reportedly coughing through her set and taking breaks to catch her breath.

Promoters behind the concert defended Houston's performance, and brushed off fears the star is in poor health. But concerns for the singer were raised again on Wednesday following her show at the Acer Arena.

Reporters at local newspaper the Sydney Daily Telegraph claim the first 50 minutes of the concert ran smoothly, but the show began to deteriorate after a 13 minute break halfway through, with fans allegedly storming out of the gig as Houston began to struggle with her set.

One fan, Shane Norquay, tells the paper, "Some of it's been beautiful and some it is just horrible. It feels like she's trying to be herself but it's not working." Bernadette Latta, whose son bought her the tickets as a Christmas gift, adds, "It's terrible. I have never walked out before a concert finished but that was just terrible. I'll be suggesting my son tries to get a refund."