Houston, you have a problem. Whitney's shambolic stage show

Angry fans walked out of a Whitney Houston concert after she struggled through her set, forgot the words to songs and appeared disorientated.

The singer was described as "breathless and exhausted" and had to take a break after only two songs last night in Brisbane.

The 46-year-old, who admitted drug addiction during an abusive marriage to Bobby Brown, could not reach the high notes to her hits including I Will Always Love You and coughed frequently during songs.

She forgot lyrics, constantly turned her back on the audience and took long breaks in between songs to towel off, drink water and refresh her make-up. During some of these breaks, her brother Gary came on stage to sing.

Houston failed to properly name her backing band as she introduced them to the audience at the Brisbane Entertainment Centre.

Australian TV channels interviewed fans as they left the arena before the show had finished, with one woman telling the camera: "Houston, we have a problem. You can't sing, you forgot the words and you were the worst act we've ever seen." Robyn Holland said: "Whitney has left the building. She couldn't entertain a dead rat." Another fan added: "That was the worst concert I've been to in my life. What a waste of money." In a written statement, tour manager Andrew McManus questioned why Australians could not support someone "who has seen difficult times".

"[She] is now up on stage, warts and all, presenting herself like an open book for the world to see and they want to ridicule Whitney," he said. "I am personally amazed at the few who are trying to derail the project. If they expected to hear Whitney of 20 years ago, go buy a CD.

"If they wanted to see a true professional artist give 100 per cent, well come along and enjoy the ride of an amazing talent, on stage, letting her heart and soul out for us all to enjoy."

The Australian leg of her world tour is set to continue in Sydney, the Hunter Valley, Melbourne and Adelaide.