Ex-South Korea leader Yoon jailed 2 years over illegal polling

South Korean President Yoon Suk Yeol answers a reporter's question during a press conference at the Presidential Office in Seoul on November 7, 2024. [AFP]

A South Korean court sentenced former president Yoon Suk Yeol on Monday to two years in prison for illegally receiving free opinion polls in exchange for political support, adding to his growing legal woes.

Yoon, 65, is already in detention while appealing against a separate life sentence for leading an insurrection through his declaration of martial law in 2024.

In a separate case, a court handed Yoon a 30-year prison sentence for sending drones into North Korea to "manufacture" a crisis ahead of his martial law bid.

Monday's ruling was unrelated to the martial law decree.

It concerned allegations that he received free opinion polls between 2021 and 2022 in exchange for supporting a candidate seeking his party's nomination in a parliamentary by-election.

"The court today found him guilty of violating the political funds act and sentenced him to two years," a representative of the Seoul Central District Court told AFP.

In its ruling, the court found that Yoon -- in collusion with his wife Kim Keon Hee -- received 14 free opinion polls from the power broker Myung Tae-kyun in return for supporting a candidate whom Myung backed.

"Yoon's conduct significantly intensified public distrust in politics and undermined the people's expectations for the sound development of democratic governance," the court said in a statement shared with AFP.

"The defendant's culpability is therefore exceptionally serious," it added.

The court also convicted Myung and sentenced him to 18 months in prison.

Yoon's lawyers said they would appeal, arguing that the guilty verdict was "based solely on inference".

The latest ruling comes as former first lady Kim awaits a Supreme Court ruling in the same case on Thursday.

She was acquitted in two previous rulings.

Kim is already serving a seven-year prison term in a bribery case involving jobs allegedly provided in exchange for gifts.

She is also serving a four-year sentence in a separate case involving stock manipulation and graft.

Yoon plunged South Korea into a political crisis when he declared martial law in December 2024. The decree was swiftly voted down by opposition lawmakers, and he was later impeached and removed from office.