Former Prime Minister Tony Abbott will travel to the United States to address a conservative Christian lobby group about his views on marriage.

Mr Abbott, who on Sunday night announced he would re-contest his Sydney seat of Warringah at the next federal election, is expected to speak at the private event organised by the Alliance Defending Freedom (ADF) this week.

In a short statement to the ABC, an ADF spokesman described the organisation as “an alliance-building legal organisation that advocates for the right of people to freely live out their faith”.

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“Along with our work to defend human rights such as free speech and religious freedom, ADF affirms the good of marriage and the value of strong families around the world, particularly on behalf of children, who flourish when society honours and promotes the roles of both mothers and fathers in children’s lives,” the statement said.

“Mr Abbott has been a strong advocate for marriage and freedom throughout his career and has graciously agreed to address our private event.”

Mr Abbott is firmly of the view marriage should remain between a man and a woman, and was the subject of significant criticism over the handling of a Coalition party room debate on same-sex marriage last August.

As a result of that marathon meeting, the Coalition agreed to hold a popular vote to decide the issue.

Mr Abbott’s successor, Prime Minister Malcolm Turnbull, had publicly lobbied in favour of same-sex marriage and criticised Mr Abbott’s decision, arguing members of parliament should decide.

However, since ousting Mr Abbott from the prime ministership, Mr Turnbull has stuck to the Coalition party room’s decision.

The ADF was one of the most outspoken critics of the US Supreme Court’s decision last June to allow same-sex marriage, arguing it had overturned the rights of millions of Americans who had voted against gay marriage in their states.

The Alliance hosted a similar event last year, featuring the former US Ambassador to the United Nations, John Bolton.

– with Matthew Doran and Roscoe Whalan