The Pentagon has confirmed it will start formal talks with South Korea on deploying an advanced missile defence system to South Korea to counter the growing threat of North Korea's weapons capabilities after its rocket launch on the weekend.

U.S. military officials have said the sophisticated system called Terminal High Altitude Area Defence (THAAD) was needed in South Korea.

South Korea said on Sunday it and the United States would begin talks on the THAAD, after North Korea launched a long-range rocket earlier carrying what it has called a satellite.

"We feel confident that our posture right now is adequate to the challenge and the task," Pentagon spokesman Peter Cook said Monday. "But we do think adding THAAD would simply only improve that posture and improve, if you will, the reassurance level for our allies."

In another development, Gen. Joseph Dunford, chairman of the U.S. Joint Chiefs of Staff, will be in Hawaii, home to U.S. Pacific Command, to discuss North Korea's launch with his Japanese and South Korean counterparts this week.

The meeting, whcih was scheduled before the launch, is part of continuing efforts to strengthen military ties among the three countries, sources have told Reuters.

It was not immediately clear whether the South Korean and Japanese chiefs of staff would participate in the meeting in person or via secure video teleconference, the sources said.