North Korea has confirmed it has tested a new submarine-launched ballistic missile, calling it a "significant achievement" in its efforts to contain external threats and bolster its military power.

The test-firing on Wednesday came ahead of a weekend resumption of nuclear diplomacy with the United States.

That diplomacy largely remains stalemated after the February breakdown of a second summit between President Donald Trump and North Korean leader Kim Jong Un in Vietnam.

North Korea has recently warned its dealings with the United States may end if it fails to come up with new proposals to salvage the nuclear diplomacy by December.

The Korean Central News Agency (KCNA) said the test of the Pukguksong-3 missile off its east coast was successful and "ushered in a new phase in containing the outside forces threat to (North Korea)".

North Korea having an ability to fire a missile from a submarine is a threat to the United States and its allies because such launches are harder to detect early enough to respond. The use of solid fuel also increases a weapon's mobility.

After Wednesday's launch, the US State Department called on North Korea "to refrain from provocations, abide by their obligations under UN Security Council resolutions, and remain engaged in substantive and sustained negotiations to do their part to ensure peace and stability on the Korean Peninsula and achieve denuclearisation."