Gay marriage debate in Australia gets ugly.

A protester shows his colours during a gay rights march through Sydney to the ruling Labor Party's conference to stage a mass "illegal wedding" stunt on August 1, 2009. The national Labor conference voted to develop a system for the registration and recognition of same-sex relationships, after gay rights advocates failed to gather enough numbers for a resolution to legalise gay marriage. Australian Prime Minister Kevin Rudd won the 2007 election on a platform that supported the former conservative government's legal definition of marriage as a union between a man and a woman. AFP PHOTO/Torsten BLACKWOOD (Photo credit should read TORSTEN BLACKWOOD/AFP/Getty Images)

Australia’s debate over whether to legalise same-sex marriage has become increasingly bitter, with accusations of bullying and calls for a doctor to be deregistered after she rallied against legalising same-sex marriage.

As the federal government pressed ahead with plans for a controversial national plebiscite, Dr Pansy Lai, a Chinese-born paediatrician in Sydney, found herself at the centre of the debate after appearing in a television advertisement for the “no” campaign.