North Korea has claimed the missile it launched over the weekend was a new type of long-range ballistic rocket that can carry a heavy nuclear warhead.

Leader Kim Jong-un was said to have witnessed the test and "hugged officials in the field of rocket research, saying that they worked hard to achieve a great thing," according to North Korea's official Korean Central News Agency (KCNA).

The missile flew for half an hour and reached an unusually high altitude before landing in the Sea of Japan, the South Korean, Japanese and US militaries said. Tokyo said the flight pattern could indicate a new type of missile.

Sunday's launch was an immediate challenge to South Korea's new leader Moon Jae-in, a liberal elected just five days earlier who expressed a desire to reach out to North Korea.

KCNA called the missile a "new ground-to-ground medium long-range strategic ballistic rocket Hwasong-12 ... capable of carrying a large-size heavy nuclear warhead".

The UN Security Council will hold closed consultations about the launch on Tuesday afternoon.

The Security Council has adopted six increasingly tougher sanctions resolutions against North Korea.

President Donald Trump's administration has called North Korean ballistic and nuclear efforts unacceptable, but it has swung between threats of military action and offers to talk as it formulates a policy.

David Wright of the Union of Concerned Scientists, said the missile could have a range of 2,800 miles if flown on a standard, instead of a lofted, trajectory - considerably longer than Pyongyang's current missiles.

He said Sunday's launch - the seventh such firing by North Korea this year - may have been of a new mobile, two-stage liquid-fuelled missile North Korea displayed in a huge April 15 military parade.

Japanese Prime Minister Shinzo Abe told reporters the launch was "absolutely unacceptable" and that Japan would respond resolutely.

The White House took note of the missile landing close to Russia's Pacific coast and said that North Korea has been "a flagrant menace for far too long".