Moon's comments came amid a controversy that late President Roh Moo-hyun, whom Moon served under as chief of staff, said in 2007 South Korea would not maintain on the Yellow Sea border that Pyongyang has disputed, Yonhap news agency reported.
"I will ensure a firm defense capability that will not a allow a single provocation from North Korea in the Yellow Sea," said Moon, a member of the Democratic United Party.
"Based on that defense capability, I will end military confrontation in the Yellow Sea and actively pursue dialogue toward peace," Moon, the 59-year-old said.
National security is a key political issue ahead of December's presidential election. North Korea has never recognized the sea border, known as the Northern Limit Line
"[The 2003-08 Roh administration] held military talks with North Korea and established a system to prevent skirmishes in the Yellow Sea," Moon said. "During those five years, there wasn't a single military clash not only along the NLL but also along the [inter-Korean land border]."