SEOUL, Oct. 31 (Yonhap) -- South Korea's first-ever female prime minister was acquitted on Monday of receiving illegal political funds, a decision expected to help her clear barriers to her political aspirations.

Han Myeong-sook, who worked as prime minister between 2006 and 2007 under the late liberal President Roh Moo-hyun, was accused of taking about 900 million won (US$811,541) from Han Man-ho, head of a local construction company, in violation of a law banning politicians from raising funds from supporters without issuing a receipt.

The Seoul Central District Court ruled the former official not guilty of illegal fund-raising after deeming unreliable the businessman's statement to prosecutors that he provided the money to the politician.

The ruling came one and a half years after the 67-year-old politician was cleared by a local court of taking $50,000 in bribes from another businessman in return for personal favors. The bribery case is now pending at a higher court after an appeal by the prosecution.

In the latest case, the prosecution had demanded a four-year prison term for the former premier along with an order that she forfeit the sum prosecutors said she took from the businessman during and after her term.

Judge Kim Woo-jin dismissed financial transaction records and telephone call history from Han, the businessman, which the prosecution had submitted as evidence for the charges, saying they do not build a case sufficiently.

The judge also turned down the businessman's remarks made during prosecution interrogations, ruling them unreliable and fabricated.

"The only direct evidence for the charges is Han Man-ho's statements, which cannot be deemed trustworthy due to a lack of consistency and reasonability as well as some discrepancy with objective facts," the judge noted.   

With Monday's decision, the prosecution will likely come under criticism that it went overboard with the investigation into the former prime minister.

The ruling is also expected to fuel the opposition's offensives over what they call partial investigations into those who were in power under the previous government and open the way for the former two-term lawmaker to once again pursue her political career.

She ran for the Seoul mayoralty in 2010 on the main opposition Democratic Party's ticket against former mayor Oh Se-hoon of the ruling Grand National Party, who narrowly beat Han to assume the post.

Oh's resignation in August spurred speculation that Han may seek the post again, but a pending court decision reportedly kept her from making a bid.

Some critics denounced the charges as a politically oriented move as prosecutors opened their investigation right after the 2010 Seoul mayoral election.