Rival party lawmakers expressed concerns about the nation's air defense system at Friday's assembly session.
They raised questions about why the government was not prepared for an infiltration of North Korean drones.
"Security is vital for national interest. How well prepared are we for such unprecedented intrusions by the communist state?"
"We are considering buying a radar system that can detect low-flying objects. We are working with the defense ministry to devise a series of measures to bolster our air defense system."
Lawmakers of the main opposition New Politics Alliance for Democracy honed in on the
alarming fact that an unmanned aircraft found in Paju, Gyeonggi-do province flew over the presidential compound last month and snapped dozens of pictures.
They raised concerns that the drones could be used to carry out attacks.
"I think South Korea has a serious security dilemma. We must not neglect the fact that the drones could be loaded with bombs or chemical weapons."
"The unmanned aerial vehicles are rudimentary spy drones. But Pyongyang may develop more advanced drones for attacks in the future. We are drawing up measures."
The opposition lawmakers also grilled cabinet ministers over whether Seoul was prepared to counter a future nuclear test by Pyongyang.
They urged the government to hold bilateral summit talks between South and North Korea.
Prime Minister Chung said if Pyongyang does conduct a fourth nuclear test, the government will work with the UN Security Council to slap harsher sanctions on the Kim Jong-un regime.
"On Monday, the National Assembly will resume the interpellation session with a focus on the economy. Follow-up measures to the nation's biggest-ever personal data leak earlier this year are expected to dominate the discussions.
Ji Myung-kil, Arirang News."