Hours before a vote on whether to impeach Thailand's ex-prime minister over a failed rice subsidy scheme, the country's attorney general announced that the former leader would face corruption charges in the same case.

Former Prime Minister Yingluck Shinawatra was accused last year of dereliction of duty over the failed program, which the country's anti-corruption commission said had cost Thailand $4 billion (3.5 billion euros). Under the scheme, the government bought rice from farmers at prices far higher than on the open market, leading to huge stockpiles building up.

"The Attorney General's Office has considered witnesses and evidence submitted by the working team along with all witnesses and evidence from the National Anti-Corruption Committee and we agree that the case substantiates a criminal indictment charge against Yingluck," the director general of the attorney general's office said.

The indictment was expected in early March, according to news agency AFP. Reuters news agency also reported that the formal charge could result in a maximum 10-year prison sentence.

Yingluck was removed from office in May in a controversial court ruling shortly before the military seized power in a coup. Months of mass protests against her rule preceded her departure.

Earlier this month, Thailand's military-appointed assembly opened impeachment proceedings against her over the rice subsidy scandal. It was expected to reach a decision on Friday. If found guilty, she will be banned from politics for five years.

kms/bk (AP, AFP, Reuters)