Hyun In-taek, a unification policy adviser to President Lee Myung-bak, recalled the North's launching a long-range rocket in April 2009, followed by its second nuclear test a month later, Yonhap News Agency reported.
"We already had the exact same situation in 2009," Hyun said. "The whole message North Korea tries to convey through its plan for a long-range missile launch is that a nuclear warhead can be loaded onto the missile.
"By doing this, North Korea thinks the effect of their blackmail will be greater. This is part of their underlying and careful political calculation. Therefore, it is highly likely they will follow the same pattern."
North Korea says it plans to launch the long-range rocket between April 12 and 16 to put a satellite into space orbit.
South Korea, the United States and other nations have criticized the planned launch, saying it's in reality a test of North Korea's improved ballistic missile technology.
Hyun called on the international community to "respond to North Korea with determination."
"The behavior of North Korea we perceive now indisputably damages the stability and peace of the Korean Peninsula and Northeast Asia," he said. "If their behavior is tolerated, we will plunge into deeper security dilemmas."