Sia competed in a medley double at the 2000 Summer Olympics in Sydney. She achieved FINA B-standards of 2:20.64 (200 m individual medley) and 4:52.52 (400 m individual medley) from the Southeast Asian Games in Bandar Seri Begawan, Brunei. On the first day of the Games she placed twenty-fifth in the 400 m individual medley. In heat four, she finished at the bottom of the pack in a poor time of 4:59.18, more than six seconds slower than her national record. Two days later, in the 200 m individual medley, Sia posted a time of 2:20.64 in heat two but finished in thirty-first place among 36 other swimmers from the prelims.