Former Nepalese Prime Minister Sher Bahadur Deuba has been charged with misuse of public funds while in office.
Mr Deuba says he is subject to a vendetta
The charges were laid by Nepal's controversial anti-corruption commission, set up by King Gyanendra after he seized power in a royal coup.
One of the king's first steps in the coup was to sack Mr Deuba's government.
Mr Deuba, who is under arrest, has refused to testify before the commission, which the opposition say is a tool to muzzle dissent.
King Gyanendra seized power on 1 February because he said Nepal's democratic political parties had failed to deal with the country's Maoist insurgency.
Mr Deuba was arrested last week by the Royal Corruption Control Commission (RCCC) after he refused to answer questions over his role in a multi-million dollar water project.
He has said he will not co-operate with the commission which he describes as an unconstitutional body.
The commission has now charged him and six other former ministers with the misappropriation of government funds.
In an interview with the BBC, commission spokesman Prem Raj Karki confirmed that Mr Deuba was still in detention, although the others have been released on bail.
The RCCC has sweeping powers to investigate, arrest and punish anyone on charge of corruption.
Furthermore, it can detain suspects for up to six months and impose fines if suspects are deemed to have "obstructed" its investigations.
Last Saturday the king lifted a state of emergency that he imposed when he seized power. However he has given no indication that he intends to restore multi-party democracy sooon.