A campaign to end modern slavery started by WA mining magnate and philanthropist Andrew Forrest's family has secured an historic agreement signed by the leaders of the world's religious faiths.
In the agreement, signed at the Vatican in Rome as Mr Forrest and his daughter Grace looked on, the leaders pledged to work to eradicate slavery by 2020.
The declaration was signed by religious leaders from around the world, including the Pope, the Archbishop of Canterbury Justin Welby, as well as Orthodox, Hindu, Buddhist, Jewish and Muslim leaders.
The agreement said that modern slavery, through human trafficking, forced labour and prostitution, organ trafficking and any relationship which "fails to respect the fundamental conviction that all people are equal and have the same freedom and dignity is a crime against humanity".
The leaders agreed to "inspire spiritual and practical action by all global faiths and people of goodwill everywhere to eradicate modern slavery across the world by 2020 and for all time".
The Forrests' involvement began after Grace was shocked by what she saw when she visited a children's refuge in Nepal on a school trip six years ago.
In 2012, the family set up the Walk Free Foundation, which worked with the Vatican this year to establish the Global Freedom Network to tackle slavery.
The Walk Free Foundation's global slavery index estimates more than 36 million people across the world are caught in conditions of modern slavery.
Mr Forrest said the declaration signed by the faith leaders was unprecedented.
"It is the first time in history that both Sunnis and Shi'ites have joined with the Catholic, Anglican and Orthodox as well as Jewish, Hindu and Buddhist faiths to publically work together to eliminate slavery," he said.
"It is also the first time that both the Sunni and Shi'ite religions have joined together to work on a common global initiative and the first time that leaders of the Anglican and Catholic churches have come together on such a complex social issue since the Reformation."
Mr Forrest said the agreement was the foundation for ensuring that people of faith worldwide had a clear message from their leaders that slavery was a crime against humanity.
He said the leaders had shown great warmth and "tremendous courage" to join together.
Mr Forrest called on global businesses and governments around the world to take the action needed to reach the leaders' goals.
It is the first time Sunni and Shi'ite religions have joined to work on a common global initiative."