Law Minister Anisul Huq said the President was expected to issue the ordinance on Tuesday.
A series of violent sexual attacks in recent weeks has triggered protests in the capital, Dhaka, and elsewhere.
Local human rights groups say rapes have surged in the country. Ain-o-Salish Kendra, a women’s rights group, said 889 rapes, including many gang rapes, occurred between January and August. At least 41 victims died, it said.
Rights groups say many more cases remain unreported because of fears of harassment by influential people. Bangladesh’s judicial system is painstakingly slow and cases often take years to conclude.
Protests broke out in recent days after a video of a group of men stripping and attacking a woman in a south-eastern district went public through Facebook. An investigation by the country’s National Human Rights Commission found the woman in the video had been raped repeatedly and terrorised over the last year.
In another case, a woman was dragged into a college dorm from a car in which she was travelling with her husband and gang raped. Several members of the ruling Awami League’s student wing were arrested.
Prime Minister Sheikh Hasina said she would bring those responsible to justice.