South Korean opposition lawmakers Sunday stepped up criticism of the government's plan to reorganise the state railway, a day after a mass rally in protest at feared layoffs. The government this month announced a plan to spin off part of state-run Korea Railway (Korail) and allow other state-run firms to buy the shares in the spinoff. It said the move was aimed at revitalising the debt-ridden railway, that has suffered from chronic and growing losses. But thousands of railway workers including train drivers suspect the move is a prelude to privatisation along with mass layoffs and pay cuts, and have staged a partial strike since December 9. At least 20,000 workers, activists and supporters staged a rally in central Seoul Saturday, demanding the scrapping of the changes. The rally -- the biggest in the country this year -- was staged amid high security involving some 13,000 police officers. No major incidents were reported. Sul Hoon, a lawmaker of the main opposition Democratic Party (DP), slammed President Park Geun-Hye for pushing ahead with the plan despite calls for more negotiations with workers. "The latest railway crisis will never be resolved by merely cracking down (on workers on the strike)," Sul said in a meeting with Korail union members along with dozens of other DP lawmakers on Sunday. Some 30 union leaders have been accused of an offence of disrupting business and are being sought by police. Three of them have been arrested, while some others have taken shelter at a temple in central Seoul. Police rarely enter a temple or church for fear of sparking a backlash. "The current deadlock will never be solved unless President Park changes her mind," Sul said, accusing her administration of "extreme bigotry and obstinacy". Woo Won-Shik, a senior DP member, also urged the government to resume talks with workers to end the partial strike that has caused weeks of delays or cancellations in train and subway services across the country. "It's time for Park to make a decision. Otherwise she will be faced...with opposition across the country," Oh Byung-Yun, floor leader of the leftwing Unified Progressive Party, told a press conference on Sunday. Some 6,600 Korail workers -- nearly a third of the total of 20,473 -- were on strike as of Sunday, the company said.