Fairfax Media revealed on Monday that Mr Abbott is on his way to the US to address the group. Former prime minister Tony Abbott. Credit:Alex Ellinghausen A spokesman for the group told Fairfax Media in a statement that Mr Abbott, who "has been a strong advocate for marriage and freedom throughout his career", had "graciously agreed to address our private event". But the spokesman declined to explain the nature of the event, say where or when it was to be held, or say if Mr Abbott was being paid for his attendance. The news came as a US lawyer associated with the group was arrested on child pornography charges, after being accused of taking a teenager across the border to Canada, where they engaged in sexual activity that was then filmed.

In recent years the ADF has been at the forefront of conservative attempts to undo key sections of US President Barack Obama's signature healthcare laws. ADF lawyers have argued in a string of legal challenges that religious employers – such as universities, hospitals and schools – should not be made to facilitate their employees' access to health insurance that includes coverage for contraception and or abortion. An article by the Southern Poverty Law Centre, which tracks hate groups in America, says that since it was founded by 30 religious leaders in 1994 the ADF has grown to an organisation with an annual budget of $US30 million ($43 million) with 44 in-house staff and a network of 2200 allied lawyers who work to further their Christian ideology through the law. "Their work is fanning the flames of anti-gay hatred that already exists in many of the countries where they are injecting themselves. As in Uganda, American groups have been propagandising about the 'recruitment' of young schoolchildren, the allegedly depraved and diseased lives of LGBT people, the paedophilia that is supposedly common among gay men, and the destruction of Christianity and the institution of marriage that they seem certain ending anti-LGBT laws will lead to," writes the Southern Poverty Law Centre. "This vicious propaganda, born and bred by American ideologues, has found fertile soil across the globe."

Their work is fanning the flames of anti-gay hatred that already exists in many of the countries where they are injecting themselves. Southern Poverty Law Centre Much of the ADF's money is raised anonymously, though some of the wealthiest names associated with the Republican Party donated. Richard and Helen DeVos Foundation, which is funded by the billionaire founder of Amway and owner of the Orlando Magic of the NBA, gave at least $US235,000 in unrestricted grants between 2001 and 2010. Edgar & Elsa Prince Foundation gave $US150,000 between 2010 and 2012. God's Gift, a foundation run by medical supply company chief executive Helen Lovas until her death in 2014, gave ADF $US1 million between 2010 and 2012. The ADF has intervened in the landmark case Citizens United v Federal Election Commission, which opened the door for wealthy corporations and individuals, such as those who have donated huge sums to the ADF, to flood the US political system with money. The ADF also assisted on a case which affirmed the right of St Patrick's Day Parade organisers to exclude homosexuals and to allow the Scouts to discriminate against gays. One of the most controversial cases involving the ADF was a bill in the Arizona legislature that would have allowed private businesses to discriminate against homosexuals. The bill was so extreme it was rejected by a conservative Republican governor. Follow FairfaxForeign on Twitter