The Solicitor General in the Philippines, Romeo de la Cruz, said a 1993 conviction against Mrs Marcos, the widow of the late President Marcos, had been based on an erroneous application of the law.

Imelda Marcos: dropped out of May's elections

Mrs Marcos was convicted of having granted leases on government-owned land to the Philippine General Hospital Foundation, which she headed.

The land was said to have been leased to Mrs Marcos' organisation at "improperly low rates", but the solicitor general says there is no evidence to prove this.

The land was then sublet to another company at much higher rates.

The Supreme Court has in the past rarely reversed a recommendation from the soliticitor general.

Mrs Marcos, 68, also faces numerous other criminal and civil cases related to the 20-year rule of her husband.

She and her husband have been accused of stealing billions of dollars during his presidency, which lasted until a popular revolt in 1986.

The former president died three years later in exile in Hawaii, his wife remaining free on bail while an appeal was being considered.

Mrs Marcos originally intended to compete in last month's Presidential elections, but later dropped out and called on her supporters to vote for the candidate who eventually won, Joseph Estrada.