The South Korean National Assembly has been adjourned until Friday after supporters of President Roh Moo-hyun blocked an impeachment vote.
President Roh was criticised by South Korea's election watchdog
Members of the breakaway Uri party, who back Mr Roh, occupied the speaker's desk to prevent a vote taking place.
The opposition had said it had the necessary two-thirds majority needed to pass the impeachment vote, the first in South Korea's history.
Mr Roh's powers could be suspended for up to six months if the vote passed.
The two opposition parties, the Grand National Party (GNP) and the Millennium Democratic Party (MDP), have joined forces over the impeachment vote.
The GNP leader in the Assembly, Hong Sa-duk, said the number of MPs ready to support impeachment was in excess of the required two-thirds majority, or 181 of the 271 seats.
"The fate of President Roh has been sealed," he said.
A National Assembly official said the session would be reconvened on Friday, staring at 1000 (0100 GMT).
Earlier President Roh rejected opposition demands that he apologise for a minor breach of election rules.
"If people say I should apologise just to avoid being impeached... I cannot accept it," he told reporters.
The impeachment motion was tabled on Tuesday, after an election watchdog ruled that Mr Roh had breached election rules by recommending voters back the Uri Party at the election.
Mr Roh said at a televised news conference that while some might consider him to be "in the wrong", it would "not be helpful for political development to leave a bad precedent by striking a deal for political reasons" over the issue.
Mr Roh's supporters in the Uri Party have staged a sit-in in protest
If the National Assembly votes to impeach Mr Roh, the measure then goes to the constitutional court where six out of the court's nine judges will have to back the impeachment.
The president's powers would be suspended until the constitutional court ruling, which could take up to six months.
Mr Roh came to office last year promising to clean up corrupt links between government and big business.
He has been severely weakened by evidence that his closest aides and family members have taken illegal funds from businessmen.
Prosecutors have accused them of taking about $10m in illegal donations from businessmen.
But opposition aides are accused of having taken even more money, and Mr Roh said earlier this year that he would resign if his camp was found to have taken more than a tenth of the illegal funds raised by the opposition.