But a government committee said the bridge disaster was not the fault of any body or agency.
The group also found financial ties between individuals in government and businesses responsible for rights violations.
Ninety-five political leaders from 44 Asia and Pacific nations met in Phnom Penh on Thursday to strengthen their role in the region.
The CAPDI is part of the International Conference of Asian Political Parties, which is made up of 300 members.
Some 2,700 people from 14 provinces contributed corruption complaints earlier this year.
The Diamond Bridge stampede left 351 dead and 395 injured at last count, one of the worst disasters in Cambodia, in decades.
Prime Minister Hun Sen said on Monday no one would be fired as a result of the disaster, and that no single person deserved the blame.
Monday marked the seven-day funeral ceremonies for the 351 casualties, a figure revised upward Monday from 345.
The 2011 budget that the Cambodian National Assembly recently passed totaled to $2.4 billion.
The observer dismisses the transferring of cases to local courts as a plausible solution to the court's financial problems.