He told a political rally Thursday that HSBC's commercial banking license in the country would be cancelled if the bank was found to have broken rules, if he comes to power.
HSBC, JPMorgan and Barclays have been mandated to raise the money.
"HSBC maintains the highest standards in all our banking operations and adheres to all laws and regulations in every country in which we operate," HSBC Sri Lanka said in a statement.
"HSBC is one of the largest financial organisations in the world and has a major footprint in the international capital markets based on integrity, longevity, commitment and consistency.
"HSBC also has a long and proud history in Sri Lanka stretching back more than 100 years."
The mandate was given before the US sub-prime default problem hit debt markets. Emerging market de