Park addressed a foreign affairs committee Tuesday about security concerns over North Korea. The North Korean government withdrew from the armistice that halted the Korean War and has escalated its war rhetoric in the wake of a February nuclear test.
"Though it is a must to strike back strongly in the event of North Korean provocations, what is just as important is for us to keep North Korea from even harboring provocations through strong diplomatic and military deterrence," Park was quoted by South Korean news agency Yonhap as saying.
The North Korean government announced Tuesday through its official Korean Central News Agency that it will restart work at the Yonbdyon nuclear complex, which includes a uranium enrichment plant and a 5-megawatt reactor.
The reactor was idled in 2007 following talks meant to encourage North Korea to abandon its nuclear ambitions in exchange for international assistance.
White House spokesman Jay Carney said North Korea wasn't accomplishing anything through provocation.
"I would note that despite the harsh rhetoric we're hearing from Pyongyang, we are not seeing changes to the North Korean military posture, such as large-scale mobilizations and positioning of forces," he said.