Bangladesh's anti-corruption agency has filed charges against two former prime ministers over business contracts awarded to a Canadian gas company during their terms, a police official said Sunday.

The Anti-Corruption Commission filed separate cases against two former leaders Sheikh Hasina and her archrival Khaleda Zia, Dhaka Metropolitan Police official Lutfur Rahman said.

The charges resulted from contracts awarded to Calgary-based Niko Resources Ltd., allegedly without proper bidding procedures, Rahman said.

Hasina, the prime minister from 1996-2001, and Zia, who ended her latest five-year term in October 2006, are both in jail pending trial on other corruption charges.

Bangladesh, a parliamentary democracy since 1990, is currently run by an interim government backed by the country's influential army. The government took over in mid-January after weeks of violent street protests over political reforms.

Rahman said some other bureaucrats and political colleagues of Hasina and Zia, and the company's local representative have also been charged in two cases.

The anti-corruption agency claimed that Bangladesh lost millions of dollars because of the "illegal deals" that allowed Niko Resources to explore for gas at the Tengratila field in Sunamganj district, 175 kilometres northeast of the capital, Dhaka.

Officials from Niko Resources could not be reached for comment while colleagues of Hasina and Zia would not immediately make any statements.

In 2005, Zia's government held the Canadian company responsible for two blowouts in the field and demanded compensation.

Also in 2005, Zia's administration forced a junior minister to resign for taking a Toyota Land Cruiser Cygnus from Niko Resources in return for giving the company some benefits and delaying the claims for the compensation.

Niko is also involved in another gas field from where the company has been supplying gas to the country's national grid since November 2004.

Bangladesh has proven natural gas reserves of up to 425 billion cubic metres. Foreign companies have invested millions of dollars to explore and produce gas alongside state-run companies.