The North Korea Refugee Adoption Act instructs the US State Department to devise a comprehensive strategy to facilitate the adoption of North Korean children by US citizens.
US Republican lawmaker Ileana Ros Lehtinen, a key backer of the bill, said late last year that the legislation aims to "provide loving families for some of the world's most endangered children."
The bill would "require the State Department to take a broad look at the diplomatic and documentation challenges facing American families who would like to adopt North Korean orphans, and report to Congress on potential strategies to address them," said Ros Lehtinen, chairwoman of the House Foreign Affairs Committee, speaking on the floor of the US legislature.
The measure was passed by the House in September and by the Senate last week. It must still be signed by President Barack Obama.
The measure passed as it emerged the number of North Korean refugees fleeing to the South fell sharply last year, officials in Seoul said, with activists citing crackdowns and tighter border controls.
A total of 1,508 North Koreans arrived in the South in 2012 - nearly all of them via China - down from 2,706 the previous year, the Unification Ministry said.
Activists said the North had cracked down on people trying to flee the country under new leader Kim Jong-un, who took power following the death of his father Kim Jong-Il in late 2011. Supporters of the measure said many North Korean children become orphaned or stateless when their families flee with them to China or other neighboring nations, and that the youngsters often are left without the proper care.
But many children who remain in North Korea fare no better, Ros Lehtinen said.
"We are all too keenly all aware of the extreme repression, malnutrition, and poverty suffered by so many inside North Korea today. Those threats often take the greatest toll on children," the Republican lawmaker said.
Any efforts to facilitate adoptions, Ros Lehtinen said, would ensure that the North Korean adoptees are genuine orphans, and not victims of child trafficking.
The author of the bill, Republican Representative Ed Royce, will take over the chairmanship of the House Foreign Affairs Committee from Ros Lehtinen when Congress convenes a new session next week.
The United States is home to the largest ethnic Korean population outside of Northeast Asia, with nearly two million Americans of Korean descent.