In many cases, these laws contribute to homelessness, hunger and ill health for divorced or separated women and their children, the rights body said in a new report.
The UN Development Programme (UNDP) and the World Food Programme (WFP) have recorded significantly higher levels of food insecurity and poverty among female-headed Bangladeshi households.
"Bangladesh is world famous for programmes meant to reduce women's poverty; yet for decades it has ignored how discriminatory personal laws drive many women into poverty," said Human Rights Watch.
"With many women precariously housed or struggling to feed themselves when their marriages break down, Bangladesh should immediately reform its personal laws, fix its family courts, and provide state assistance to poor women."
Human Rights Watch called upon Dhaka to urgently reform the personal laws, making economic rights for women a key focus.
The Law Commission of Bangladesh has recently taken important steps to review personal laws on marriage, separation and divorce, and recommended changes this year.
Women's rights advocates and academics contributed to this review process, and have long pressed for such reforms.
The Bangladesh government should take this process forward and end legal discrimination against women within marriage, ensure women's equal right to marital property, streamline family court procedures, and improve access to social assistance programmes.
The 109-page report documents how the country's discriminatory and archaic personal laws impoverish many women at separation or divorce, and trap some women in violent marriages because they fear destitution.
Current laws deprive women of an equal right to marital property. The limited entitlements these laws offer women are poorly enforced by family courts and local government arbitration councils.
Female-headed households and women facing domestic violence struggle to access critical state support and social assistance.
Together, these problems mean there is scant economic protection or security for women when marriages break down, Human Rights Watch said.
In Bangladesh, more than 55 percent of girls and women over 10 years old are married.
The UN country team in Bangladesh has identified "marital instability" as a key cause of poverty among female-headed households.
The Bangladesh Planning Commission has said that women were more susceptible to becoming poor after losing a male earning family member due to abandonment or divorce.
As Bangladesh strives to meet its poverty reduction targets under the Millennium Development Goals, it was undermining its own efforts by leaving discriminatory and poverty-triggering laws on the books, Human Rights Watch said.
The report is based on interviews with 255 people, including 120 women, as well as with judges, family court lawyers, women's rights experts, and government officials.
New York: Bangladesh's personal laws on marriage, separation and divorce trap many women in abusive marriages or drive them into poverty when couples separate, Human Rights Watch said Monday.
First Published: Monday, September 17, 2012, 10:32