South Korea's parliament impeached acting president Han Duck-soo yesterday, less than two weeks after suspending president Yoon Suk Yeol's powers over his short-lived declaration of martial law, plunging the country deeper into political chaos.

The impeachment of Han, the acting president since Yoon was impeached on December 14 for declaring martial law on December 3, has pushed South Korea's once-vibrant democratic success story into uncharted territory.

Finance Minister Choi Sang-mok now assumes the role of acting president as the person next in line under the law. He is set to speak to the military chief and consult the foreign minister and acting defence minister, a spokesperson said.

In a statement after the vote, Han said he was saddened by what the unfolding events meant for the next generation, but accepted the outcome.

"I respect parliament's decision and in order to avoid further chaos and uncertainty, I will suspend my duties in accordance with relevant laws," he said.

He added he would await the decision of the Constitutional Court to review the impeachment motion. The ruling People Power Party, which has objected to the opposition-led impeachment of Han, said it had filed a constitutional petition.

The motion led by opposition parties passed with 192 of the 300 votes amid rowdy scenes by People Power Party members who surrounded the speaker's podium, chanting that the vote was invalid and parliament had engaged in "tyranny".

Ahead of the parliamentary session, opposition leader Lee Jae-myung of the Democratic Party, which has majority control of parliament, accused Han of "acting for insurrection".

There has been overwhelming public support for Yoon's removal, opinion polls showed after his martial law attempt.

The plan for a vote to impeach Han came after he declined to immediately appoint three justices to fill vacancies at the Constitutional Court, saying it would exceed his acting role.

Until just before voting began, it was unclear how many votes were needed to impeach Han. The threshold for a prime minister is a simple majority, while a two-thirds majority is needed for a president.

Speaker Woo Won-shik declared a simple majority would constitute parliamentary approval.

Earlier, the new acting president Choi pleaded with parliament to withdraw the plan to impeach Han, saying it would do serious damage to the economy.

The South Korean won retreated to 1,475.4 per dollar, down 0.53 percent by 0707 GMT ahead of the parliamentary vote.