The South cited North Korea's efforts to move workers out of the Kaesong Industrial Complex by April 10 as an indicator to a possible missile test, CNN reported.
There are 518 workers still in Kaesong, with 39 planning to exit Monday, CNN said.
"As of now, nothing out of the ordinary has been detected," presidential spokeswoman Kim Haeng said on behalf of National Security Chief Kim Jang-soo. "If limited war is to break out, North Korea should bear in mind that it will receive damages many times over."
The security chief's comments came just three days after South Korea's defense minister said the North had moved a long-range missile to its east coast, The New York Times reported.
The missile has a maximum range of about 2,490 miles, analysts said, which means it could possibly reach American military bases in Guam.
"We believe this is a calculated move by the North ... to launch a provocation, such as a missile launch," Haeng quoted Kim as saying Sunday.
Kim said the potential missile launch, projected to be this week, is likely a scare tactic aimed at forcing peace talks between North and South Korea, with the help of the United States, China and Russia. An armistice agreement, not a peace treaty, ended the Korean war in 1953.
"We see through their motive," Kim said, adding South Korea "has no intention of attempting premature dialogue just because of a crisis."