The rupee fell to 180.70 against the dollar, compared with Tuesday's close of 180.50, hitting a fresh low for the sixth straight session.

The rupee has fallen over 17 percent so far this year, Refinitiv Eikon data showed.

Moody's downgraded Sri Lanka last week for the first time since it started rating the country in 2010, blaming the political crisis for aggravating already problematic finances.

The downgrade coincided with a decision by the International Monetary Fund (IMF) to delay discussions about its loan tranche to Sri Lanka.

A bitter row over President Maithripala Sirisena's sacking of Prime Minister Ranil Wickremesinghe on Oct. 26 and the competing influences of China and India have shattered the island's fragile ruling coalition.

The currency has fallen over 4 percent since the crisis unfolded in late October.