Transparency International, an international anti-corruption group, set a five-month timetable to give tsunami victims a chance to voice any charges of graft when aid was being distributed.
"We are giving people five months to record such misappropriation of funds, and they have to back their claims with substantive evidence," said J. C. Weliamuna, Sri Lanka's executive director of Transparency International.
About 400 state, local and international charities received pledges of up to 3.2 billion dollars to rebuild tsunami-hit areas.
But the state auditor general in September 2005 noted out of 1.16 billion dollars committed, only 13.5 percent had actually been spent.
Transparency international believes only a fraction of the aid actually went to the victims, and in the absence of proper account-keeping it has been virtually impossible to track down what happened to the cash.
"During our post-tsunami audit last year, we found instants of sloppy work and no proper method to account for the money being spent," Weliamunna said.
The agency approached 70 agencies to carry out a post-tsunami audit last year, but only six responded.
Most agencies assessed failed to follow good accounting practices.
Sri Lanka, one of the worst hit by the Asian tsunami, lost an estimated 31,000 people, while another million were left homeless.