North Korea has started preparing for a major military parade to celebrate the founding anniversary of its ruling party in the fall, a South Korean government source said Sunday.

In commemorating the 70th anniversary of the Workers' Party on Oct. 10, North Korea may also unveil a series of new weapons, such as intercontinental ballistic missiles and submarine-launched ballistic missiles, the source added.

"There are still five months left until the anniversary, but North Korea has already formed a task force to plan the celebrations, including the military parade," the source said. "The ceremonies this year will likely be much larger than those in previous years."

On May 9, North Korea boasted that it had successfully conducted an underwater test-fire of an SLBM. Military experts in South Korea, however, say the North may have several more technical hurdles to clear before its SLBMs can successfully hit a target.

They think it could take up to five years before North Korea can deploy SLBMs.

They also say Pyongyang may launch a long-range rocket around the party's founding anniversary. Should the U.N. Security Council sanction North Korea for its action, the communist regime, which has previously contested that its rocket launches are designed to send a satellite into orbit, may carry out its fourth nuclear test in protest.

It could take a few more months for North Korea to finish expanding its launch base in Dongchang-ri, North Pyongan Province.

Once it's complete, Pyongyang will be able to launch a rocket longer than the 30-meter-long Unha-3 fired in 2012, the experts added. (Yonhap)