VATICAN CITY -- Pope Francis urged governments and legislatures on Wednesday to do more to end modern-day slavery, calling for better laws and policies to prevent human trafficking, protect its victims and prosecute those responsible.

Francis also urged businesses to ensure their distribution chains are free of slave labour and asked consumers to think twice about buying goods that may have been produced by child workers or other victims of undignified working conditions.

Francis' annual peace message, released Wednesday, focused on drawing attention to the estimated 35 million people enslaved around the world and efforts to free them.

It listed victims of organ trafficking, exploited miners and farm workers, child labourers, soldiers and beggars, sex slaves, women sold for arranged marriages and even people held captive by terror organizations as all victims of slavery who deserve the world's help.

The pope, who saw firsthand the plight of prostitutes and victims of trafficking in his slum ministry in Argentina, has made the issue of modern-day slavery a cornerstone of his pontificate. The Vatican recently hosted religious leaders who committed to helping end the "crime against humanity" of slavery by 2020.

In the peace message, Francis said combatting slavery required a global effort across sectors: governments must ensure their laws governing migration, employment and adoption respect human dignity, while also protecting victims of trafficking and "leaving no room for corruption or impunity."

He urged international organizations to co-ordinate work to combat transnational trafficking. He asked businesses to be vigilant that their distribution chains don't use slave labour and for consumers to be aware that "purchasing is always a moral, and not simply an economic, act."