A government-appointed Lessons Learnt and Reconciliation Commission (LLRC) meant to address accountability issues falls dramatically short of international standards applicable to accountability processes, it said in a statement.
"The LLRC’s processes and practices have failed to win the confidence of the Tamil community."
The commission was appointed to probe allegations of human rights abuses and recommend reconciliation measures after the end of the 30-year Tamil separatist war fought mainly in the north and east in May 2009.
The end of the war has revived economic growth and resulted in a boom in tourist arrivals but much of the anticipated foreign investment had not materialised owing to lingering fears of conflict and concerns over lack of rule of law.
Concern over human rights abuses also prompted the European Union not to extend a trade deal giving Sri Lanka duty free access to its markets.
The commission report rejected allegations government forces had not done enough to prevent civilian casualties in the final stages of the war.
The TNA said most of the commission's interim recommendations made in September 2010, relating to issues like detention, land problems, law and order, administration and language, and socioeconomic and livelihood concerns, had not been implemented.
"These modest recommendations, such as the publication of a list of those in detention and the disarming of paramilitary groups, were already the subject of demands by the TNA and by Sri Lankan civil society groups for many years," it said.
"Yet, such recommendations have not been implemented, despite the lapse of more than a year since they were made."
A 'Progress Report on the Implementations of the Interim Recommendations of the LLRC', released by a government 'Inter-Agency Advisory Committee (IAAC)' appointed to ensure implementation, "reveals nothing but the lack of genuine progress," the TNA said.
The LLRC had recommended that a list of those in detention be published, as many people did not know of the whereabouts of their family members in detention, an issue the TNA has raised on a number of occasions with the government in public and in private.
"Despite repeated promises that such a list would be made public, no such list has been made public nor have family members been given access to it," the TNA said.
"The IAAC, headed by the Attorney General, does not make even passing reference to a list of detainees in its Progress Report."
The commission also recommended that people who are discharged be given a certificate to prevent being re-arrested but even that recommendation had not been implemented either, the TNA said.
"The failure of the government to implement these modest interim recommendations is telling evidence of the government’s unwillingness to take minimal steps to restore a semblance of normalcy in the North and East.
"Such blatant disregard for the LLRC’s interim recommendations, made more than a year ago, establishes an important indicator as to the fate that awaits the LLRC’s final recommendations," the TNA said.
"Hence, failure to implement these modest interim recommendations signals, if not confirms, the government’s lack of commitment to implement the Commission’s final recommendations."