The elder brother of former President Lee Myung-bak Tuesday denied alleged influence peddling involving the appointment of the head of South Korea's top steelmaker POSCO.

"I did not," Lee Sang-deuk, a former six-term lawmaker, told reporters when asked if he illegally used his position to help get former POSCO Chairman Chung Joon-yang appointed. "I explained everything well to clear up any misunderstandings."

The 80-year-old former lawmaker emerged from the Seoul Central District Prosecutors' Office in southern Seoul past midnight after a 14-hour interrogation.

Prosecutors suspect the company gave business favors to TM Tech., a local firm owned by Lee's close acquaintance, in return for help with the appointment.

He also refuted the allegation he was involved in the company's stashing away of slush funds, saying, "Where are these slush funds?" 

The elder Lee could have gained personal profit from the about 2 billion won ($1.6 million) his acquaintance, identified only by his surname Park, received in dividends from TM Tech. Park is a major shareholder of the company, prosecutors said.

Lee appeared before the office around 10:30 a.m. Monday and denied the allegations that he was involved in landing contracts for TM Tech or that he used some of the money for his political funds.

It has been three years since Lee was last summoned by prosecutors on bribery charges. He was found guilty by the Supreme Court and served a year and two months in prison until September 2013.

TM Tech officials declined to comment on the case.

The summons is the latest in a series of investigations into suspicious deals and alleged slush funds created at POSCO between 2009 and 2014. (Yonhap)