A hotel guest at Perth's Hyatt Regency claims that pop star Justin Bieber yelled out verbal abuse at a woman chatting with friends on a pool deck on Sunday afternoon, hours before his final Australian concert, news.au.com reports.

"There were four young girls in bikinis," Hotel guest Helen Robinett recalled to the news site. "One girl who was gorgeous looking, with long dark hair and would have been about a size 14. Justin looked over at her and said 'What are you, Hawaiian or something?' She said 'No, I'm not'. Then he said 'You look like a beached whale'...The girl said 'Are you serious' and he said 'You should go on The Biggest Loser.'...The whole pool deck heard him call this beautiful young girl a beached whale. Everyone heard. And there was silence. It was almost like his security were used to it."

According to Robinett's daughter, 21-year-old Gabrielle Blair, the girl "was almost in tears" after the string of insults, while Robinett echoed her daughter's comments and said that the girl looked "deflated."

"I saw Bieber make a gesture with his hands to imitate a large belly as he spoke to the long haired girl and I heard him say something about The Biggest Loser and he was pointing at her - and I saw the girl and her friends leave, downcast," said another guest who had arrived on the pool deck shortly before the incident. "I also told her not to take any notice of him as she walked past us, I'm not sure if she heard me. Bieber seemed to think he was funny, he was smiling and looking to his burly minders for their approval."

Robinett, who works in Melbourne as an image consultant and was in Perth for business, made a formal complaint to the hotel on behalf of Bieber.

"They said the girl was OK and she was a Bieber fan," she told news.au.com. "She may appear OK, but I work in styling and fashion, I know how women view their bodies, what body image issues women have. That kind of comment can have a serious impact and repercussion. That's why I'm so upset about it. I'm bloody angry. He's nothing without his fan base."

She added that Bieber jumped into the pool from an upper level of the hotel, calling out to two little boys below, 'Hey kids, don't do this." While Bieber's security team asked everyone to refrain from photographing the star, Robinett managed to take one of Bieber and his entourage on the pool deck.

"I understand he's 19, he's surrounded by meat-heads who pander to his every need. He's immature, he needs leadership and guidance. He may come through, I hope he lives long enough to learn some lessons and do some good things," she said.

The hotel declined to confirm whether or not the formal complaint had been made.