Floor leader Joo Ho-young will also join them after the party concludes its leadership contest scheduled for next Monday.
Their defections, if finalized, will reduce the number of the embattled party's legislators to 11 and strip it of its status as a parliamentary negotiating bloc, which requires at least 20 lawmakers of the 299-member National Assembly.
"Today, we will embark on a path of grand conservative unity," the lawmakers said in a joint statement. "We will strive for a grand integration to unite all conservative forces to fend off the surge in populism by the Moon Jae-in government and the escalation of the security crisis."
