Police raids have revealed an alleged network baby "farms" or "factories" in Nigeria, forcing a new look at the scope of human trafficking in the country.

At a hospital in Enugu, a large city in Nigeria's southeast, 20 teenage girls were rescued in May in a police swoop on what was believed to be one of the largest infant trafficking rings in the west African country.

The two-story building on a dusty street in Enugu's teeming Uwani district now stands deserted, shutters down.

Neighbors had long found something bizarre about the establishment, where there was virtually no activity during the day, they said.

The doctor in charge, who is now on trial, reportedly lured teenagers with unwanted pregnancies by offering to help with abortion.

They would be locked up there until they gave birth, whereupon they would be forced to give up their babies for a token fee of around $170.

The babies would then be sold to buyers for anything between $2500-$3800 each, according to a state agency fighting human trafficking in Nigeria, the National Agencyfor the Prohibition of Trafficking in Persons (NAPTIP).

But luck ran out for the gynecologist, said to be in his 50s, when a woman to whom he had sold a day-old infant was caught by Nigeria's Security and Civil Defence Service (NSCDS) while trying to smuggle the child to Lagos, the security agency said.

Statistics on the prevalence of baby breeding are hard to come by, but anti-trafficking campaigners say it is widespread and run by well-organized criminal syndicates.

Click here to read more on this story from News.com.au.