Officials from Sri Lanka's state- run petroleum corporation have been summoned before parliament following alleged imports of substandard fuel, an opposition politician said on Monday.

The Ceylon Petroleum Corporation (CPC) has been summoned to appear before a parliamentary committee appointed to probe corruption charges of state enterprises, according to main opposition, United National Party (UNP) MP Ravi Karunanayake.

Karunanayake who is a member of the Committee on Public Enterprises (COPE) said it will investigate claims of substandard imports of fuel that resulted in the stalling of more than 100 buses and several trains last week.

"The reasons for this must be found out and waste of public money stopped," he told media.

In response to complaints the government appointed a committee to study the fuel consignment and decided to delist Vitol, which is one of the largest oil traders in the world. The committee will submit a final report once investigations are complete.

The company in a statement denied releasing contaminated fuel.

"Contamination could have occurred at any of a number of points between the terminal and the end consumers. We assume the investigation taking place will test every possible point of contamination to avoid further problems,"it said.

Last year the Sri Lankan government withheld payment from Emirates National Oil Company after consumers lodged several thousand complaints of substandard fuel.