A former leader of South Korea's ruling party demanded Sunday the government re-introduce tactical nuclear weapons in a bid to counter North Korea's nuclear and missile threats.

Chung Mong-joon, who led the Saenuri Party from 2009-2010, stressed the need for the South to declare the end of an inter-Korean denuclearization deal and the withdrawal from the Non-Proliferation Treaty.

"(We) should consider and review 'all alternatives' before too late for our survival," he said on his blog.

Chung, once a seven-term lawmaker, has long called for the South to go nuclear amid the North's continued development of its nuclear arsenal.

The U.S. withdrew nuclear weapons from Korea in the early 1990s, when the two Koreas issued a joint declaration to keep the Korean Peninsula nuclear-free.

Chung said the denuclearization deal has already become null and void as the North conducted four nuclear tests, most recently on Jan. 6.

He stressed that peace can be maintained by countering nuclear threats with nuclear weapons.

"It's a Cold War lesson," he said. "Talks to get rid of nukes are possible only when there is a strong means corresponding to nukes."

Chung said sanctions and pressure on North Korea would have a limited effect and Pyongyang is expected to seek negotiations with Washington, bypassing Seoul, as a nuclear state.

That's a reason why the South needs to withdraw from the NPT, he added, citing the Article X of the treaty.

It says, "Each Party shall in exercising its national sovereignty have the right to withdraw from the Treaty if it decides that extraordinary events, related to the subject matter of this Treaty, have jeopardized the supreme interests of its country."

In the wake of the North's latest provocation, calls have grown here for the South to have its own nuclear deterrence.

Rep. Won Yoo-cheol, the floor leader of the Saenuri Party, openly said it's time for the South to have nuclear weapons for peace and self-defense.

President Park Geun-hye said she understands such a sentiment but made clear that her administration will stick to the policy of denuclearizing the entire peninsula. (Yonhap)