Justin Bieber reportedly branded a fellow hotel guest a ''beached whale''.

The 19-year-old singer shocked sunbathers on the pool deck at the Hyatt Regency hotel in Perth, Australia, on Sunday (08.12.13) when he mocked a ''gorgeous'' fan for her curvy figure.

Hotel guest Helen Robinett told website News.com.au: ''There were four young girls in bikinis. 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.

''I made a complaint to the hotel, and they said the girl was OK and she was a Bieber fan.

''He's nothing without his fan base. And he's abusing them. The girl next to me said, 'I can't believe he just said that, he's my idol.' And I said, 'Well get yourself a new idol.' ''

Helen also criticised the star - who had had the gym and pool closed for private use the day before - for his irresponsible actions around the water in front of young children.

She continued: ''There were two little boys having a ball around the pool and Justin said, 'Hey kids, don't do this,' and then jumped into the pool. He did it twice.''

A spokesperson for the hotel refused to comment if there had been any complaints about their famous guest.

The spokesperson said: ''We are a hotel, we have hundreds of guests staying with us, we simply cannot speak on behalf of every single guest that comes in and interacts with another guest. But obviously we want all our guests to feel comfortable and not intimated by anyone. We have security, as do any VIP guests, they have their own security.''