President Maithripala Sirisena today said he will appoint a special presidential commission by next week to investigate the alleged corruption during the tenure of former President Mahinda Rajapaksa.

Speaking at a gathering, he said that he was questioning himself as to why there was a delay in investigating corruption.

Crackdown on corruption and misuse of public funds were major planks Sirisena campaigned on ahead of the bitterly- fought January 8 presidential poll.

The new government has said it would investigate all financial deals approved by Rajapaksa and his brothers during his term.

Black money invested in various foreign countries is going to be investigated, cabinet spokesman Rajitha Senarathne recently said, referring to illegal capital flight.

Rajapaksa has denied all the allegations against him.

Sirisena, in his election manifesto, had pledged a 100-day programme to set up independent commissions to suggest ways to free key governance sector of political interference.

The government estimates around USD 5.31 billion were taken out of the country in 2013 alone.

The need for a presidential panel arises as the existing Commission to Investigate Bribery or Corruption is viewed weak and lacking resources for effective anti-corruption crackdown.

In 1978, a similar presidential commission had deprived former prime minister Sirimavo Bandaranaike, former minister Felix Dias Bandaranaike and top official Nihal Jayawickrema of their civic rights for their abuse of power while being in office.

In late January it was said that a high powered committee of 11 members led by Prime Minister Ranil Wickremesinghe was established to investigate corruption. However, hardly any details were known on that committee's work.