The Sri Lankan parliament erupted in anger on Thursday as the government's Office of Missing Persons bill was debated before being passed without vote.
A number of parliamentarians from the joint opposition delivered heated statements, as government figures, including the foreign minister Mangala Samaraweera attempted to pass the bill.
The debate, which was previously earmarked to take place over more than two days, was concluded in less than one hour, the Sunday Times reported.
Welcoming the passing of the bill, the US assistant secretary of state for south and central Asia, Nisha Biswal tweeted, "passage of the OMP law is a huge stride forward for Sri Lanka in advancing truth and reconciliation."
The UK government also welcomed the bill, however highlighted the need for time and perserverance to ensure that the thousands of cases of missing persons were resolved adequately.
"The UK welcomes the passing of the Office of Missing Persons Bill. It is a significant step forward on the path to reconciliation. Its implementation will help the families of people who are missing across all Sri Lanka’s communities to establish the fate of their loved ones and to foster reconciliation."
"We recognise that the Office will face a significant challenge resolving many thousands of cases. Investigating these with rigour, in ways sympathetic to the needs of victims’ families, will take time and perseverance."
The former president, Mahinda Rajapaksa had previously said that anyone who supported the bill was a traitor to the country and its armed forces.
Many Tamil organisations have expression criticism over the bill's lack of focus on accountability however.