MARK COLVIN: A young African woman who was enslaved as part of a bizarre Ghanian tribal practice is now travelling across Australia telling her story.

At the age of eight, Mercy Senahe became a slave of the Trokosi clan. She was sent to a village shrine and became the slave of a Trokosi priest in order to atone for the sins of a family member.

When she turned 13, Mercy was raped by the priest and became pregnant with the first of her four children. Mercy was finally freed with the help of an Australian aid organsition, International Needs.

Nick McKenzie reports.

NICK MCKENZIE: Mercy Senahe was born in a remote village in the south-east of Ghana. At the age of eight she was told she was being taken to a festival in a neighbouring village.

She was instead taken a Trokosi shrine and became part of a bizarre practice carried out by certain tribes in Western Africa.

A translator helped Mercy tell her story to PM.

MERCY SENAHE (translated): When we go to the town they perform some rituals around my body and presented me to the shrine.

NICK MCKENZIE: Mercy became a Trokosi slave. The slaves are usually young females given by their families to the local Trokosi priests to atone for the sins of another family member.

Mercy's translator Patience Vormarwor explains.

PATIENCE VORMARWOR: People begin to die in that family. People fall sick and die through accidents until a virgin is provided to pay for the price of that crime. So it befalls on the family to look for the most beautiful girl, present to this shrine as a bride.

NICK MCKENZIE: The Ghanian Government passed a law in 1998 banning the Trokosi slave practice, but it's unclear if it's ever been enforced. As brides of Trokosi priests, young Ghanian girls are forced to work, and repeatedly raped.

Patience Vormarwor again.

PATIENCE VORMARWOR: They are abused in so many ways, physically and emotionally and sexually. They become bride of the priest and when they turn thirteen, twelve then the priest will consummate the marriage between them and the gods. Virtually he rapes them, they become pregnant and have babies.

NICK MCKENZIE: Mercy says there were days during her enslavement she thought she would simply not survive.

MERCY SENAHE (translated): When I was in the shrine, I had to take care of myself, provide food for myself and when I had my baby I had no care for that baby so I had to struggle with life in the shrine to provide for myself and the child.

It was a mystery to me the way I survived. Sometimes I think about it I can't even explain. But I think that it is by the grace of god that I was able to go through the system and come out of it.

NICK MCKENZIE: Mercy was finally able to leave the Trokosi shrine due to the work of a small Australian aid agency called International Needs or IN.

For the last few years, Ghanian and Australian IN workers have been slowly convincing village elders to free some of the 5,000 girls still believed to be in bondage, both in Ghana and in neighbouring countries.

MARK COLVIN: Nick McKenzie.