The UN Secretary General, Mr Ban Ki-Moon has noted wth concern that despite centuries of prohibition against slavery, traditional forms still exist.
"We have also seen a disturbing emergence of contemporary forms of slavery, such as the sale of children, debt bondage and human trafficking," he said in a message on the International Day for the Abolition of Slavery which falls on December 2.
The UN Secretary General said the slave trade was abolished formally 200 years ago, but, "this flagrant human rights violation persists, fuelled by a continuing lack of respect for the dignity of human beings, a denial of their humanity and desperate poverty".
Mr. Ban noted that, domestic and migrant workers were often kept as de facto slaves, as are people working in construction, food, garment and other industries.
He said the global economic crisis could exacerbate this already alarming situation, adding, "poor people are likely to be driven further into poverty, making them more vulnerable to slavery-like practices".
Mr. Ban said those who consciously exploited them would have to extract even more to make a profit, and consumers who may not be aware of the consequences would be more likely to purchase products whose labour costs are kept unreasonably low.
The UN Secretary General said the United Nations World Conference against Racism, held in 2001, "broke new ground by declaring that slavery was and is a crime against humanity".
Mr Ban said there were an estimated 27 million victims of this atrocity, "and we must reach out to help them".
He said governments, civil society organizations, businesses and individuals must join forces to protect victims, raise awareness and demand an end to all forms of slavery and exploitation.
"We need new strategies to deal with this old curse. We need to change laws, and we need to alter attitudes and customs," Mr Ban said.
He said in just days the world would celebrate the 60th anniversary of the Universal Declaration of Human Rights.
Mr Ban said together, we must ensure that one of the most fundamental tenets - that "no one shall be held in slavery or servitude" - would soon ring true.