Another lawmaker from the ruling Saenuri Party decided to join the planned Bareun Party on Monday, increasing the number of lawmakers in the splinter group to 31.
The departure of Rep. Park Soon-ja will also reduce the number of lawmakers at Saenuri to 96.
The Bareun Party, which spun off from Saenuri last month after engaging in a factional feud with loyalists to President Park Geun-hye, initially started with 30 lawmakers.