Last month, the government announced a list of designated terrorist groups and over 420 individuals allegedly engaged in terror financing.
The 16 listed organisations included the LTTE and several key Tamil diaspora groups such as the Global Tamil Forum and the British Tamil Forum.
The diaspora groups are being described as the fronts for the LTTE in the Western world and seen as playing a key role in influencing the governments of countries like the US and the UK.
Sri Lanka views the US-led three successful UN Human Rights Council resolutions on its alleged human rights abuses as an act of favouring the LTTE.
Since the end to the conflict, Sri Lanka rehabilitated at least 11,000 LTTE members who had surrendered at the final battle.
Up to 40,000 Tamil civilians were killed at the end of the nearly three-decade-long separatist war, rights groups and experts have said.