"The death penalty for women is widely used in northern Nigeria," the Senegal-based African Rally for Human Rights said in a statement, adding that poor women were generally most vulnerable to such sentences.
In particular, the organisation, known by its French acronym RADDHO, said it was "outraged" by the stoning sentence handed down against a young mother.
Applying strict Islamic law, or Sharia, a court in northern Nigeria Monday threw out an appeal by 30-year-old mother Amina Lawal for having sex out of wedlock and ordered she be taken to a public place, buried up to her neck and put to death by stoning once her eight-month-old daughter is weaned.
RADDHO called on Nigerian authorities to "guarantee the rights of women" in the country. It also criticised the use of corporal punishment in Nigeria which it said "violated international human rights conventions against torture and cruel or degrading treatment" to which Nigeria was a signatory.
Nigeria must respect its international obligations and take measures to end practices, the organisation said.