"I feel ashamed for not being able to sustain the party since I, as president, lost support," Roh was quoted as telling key ruling party officials on Tuesday.
"I say, once again, that I will quit the party if I am a stumbling block to the party."
The former Uri party members called on
|other politicians to follow them [Reuters]
Roh offered to quit the Uri party himself last month in an effort to stop members forming a new party to distance themselves from the unpopular president ahead of the election.
The defection leaves the Uri party with 110 seats in the 299-member national assembly, pushing the opposition Grand National Party (GNP) into the number one spot with 127 seats.
In a joint statement the 23 politicians urged other members of the Uri party to follow them in the new, as yet unnamed, party.
"We will sincerely cooperate with President Roh Moo-hyun so that he can manage affairs during the remainder of his term, but we strongly reject any political intervention," the statement said. "We hope many lawmakers would join us."
The Uri Party responded with its own statement saying that the mass defections were "not a desirable act in view of political morals".
South Korea regularly sees the formation of new parties in the run up to presidential elections as politicians look to bolster their chances of winning.
The Uri party has taken a battering at recent local elections, with many members blaming the poor performance on Roh's growing unpopularity.
Many voters accuse of the president of being unwilling to acknowledge his failures in countering soaring housing prices and reviving South Korea’s stagnant economy.
At present the ruling party lacks a prominent candidate to compete against presidential hopefuls from the conservative GNP.
Recent polls show former Seoul Mayor Lee Myung-bak, a Hyundai CEO-turned-politician, as the front runner, followed by Park Geun-hye, the daughter of former military dictator Park Chung-hee – both from the GNP.