Millions of girls are at risk if the Bangladeshi government goes ahead with a proposal to lower the age of marriage to 16, Human Rights Watch warned on Monday.
The impoverished South Asian nation has one of the highest rates of child marriage in the world, despite a three-decade-old law which bans marriage for girls under the age of 18.
Human Rights Watch (HRW) said Prime Minister Sheikh Hasina's government was now considering an amendment to the Child Marriage Restraint Act, which would also lower the age of marriage of men to 18 from 21.
"Setting the age of marriage for girls in Bangladesh at 16 would be a terrible step in the wrong direction," said Liesl Gerntholtz, HRW's women's rights director. "The rate of child marriage in Bangladesh is already off the charts.
Meher Afroze Chumki, Bangladesh's junior minister for women and child affairs, said no firm decision had been made yet.
"We will discuss the proposal in detail and whatever is suitable for society, we will do that based on a consensus," Chumki told Reuters.
"There are certain countries where even 14 years is allowed to get married. To avoid any illicit relations or living together, we will consider (changing) the law."
Bangladesh has the second-highest rate of child marriage in the world, after Niger, says the United Nations children's agency, UNICEF. About 74 percent of Bangladeshi women currently aged 20 to 49 were married or in a union before 18.
Human rights campaigners say child marriage triggers a series of violations that continues throughout a girl's life such as rape, domestic violence and forced pregnancies.