Kang was the country's finance minister from 2008 to early 2009 and served as presidential economic adviser and chief of a presidential committee on industrial promotion between 2009 and 2011 before leading the state-run bank from 2011 to 2013.

"The defendant abused his status and power to peddle influence for his acquaintances," the court said.

Still, he was acquitted of allegations he pressured then-chief of Daewoo Shipbuilding & Marine Engineering Co. Nam Sang-tae to invest 4.4 billion won in the biotech firm between 2011 and 2012.

Prosecutors indicted Kang in December, saying the investment was in return for overlooking irregularities committed by Nam. The KDB is the largest shareholder of Daewoo Shipbuilding.

The court, however, said it is unclear whether Kang suggested the investment with an inappropriate intention, adding it seems he actually recommended the presidential office not reappoint Nam to lead the company.

It was not immediately known whether the prosecution will appeal the ruling.

A series of corruption allegations emerged after prosecutors launched a full-fledged investigation into the financially troubled shipbuilder last year. A trial on Nam is under way over multiple corporate crime allegations. (Yonhap)