North Korea has ratcheted up the tension in its nuclear stand-off with the US, firing a ballistic missile which flew over Japan before landing in the Pacific Ocean, 2,000 kilometres to the east of the country.

Key points: The missile was launched from the Sunan district of the North Korean capital, Pyongyang

The missile was launched from the Sunan district of the North Korean capital, Pyongyang It landed in the ocean east of Japan's north island of Hokkaido

It landed in the ocean east of Japan's north island of Hokkaido Japanese Government told people to take shelter

"These repeated provocations on the part of North Korea are not permissible and we protest in the strongest words," Japan Chief Cabinet Secretary Yoshihide Suga said.

The missile was launched at 6:57am Japan time (7:57am AEST) and splashed down at 7:16 am (8:16am AEST), some 2,000 kilometres east of the northern island's Cape Erimo, Mr Suga said.

US Secretary of State Rex Tillerson urged China and Russia to take direct action against North Korea in response to its latest missile launch.

"China and Russia must indicate their intolerance for these reckless missile launches by taking direct actions of their own," Mr Tillerson said in a statement.

He said China supplied North Korea with most of its oil and "Russia is the largest employer of North Korean forced labour".

South Korean President Moon Jae-in instructed South Korean officials to pursue "stern" diplomatic and military measures to discourage North Korea from further provocations after its latest missile launch.

Presidential spokesman Park Su-hyun said after a National Security Council meeting that Mr Moon also called for stronger preparation against the threat of biological and chemical weapons attacks by the North.

The missile was launched from the Sunan district of the North Korean capital, Pyongyang and landed in the ocean east of Japan's north island of Hokkaido.

The Japanese Government told people to take shelter and warned them to stay away from anything that could be debris.

The unidentified missile reached an altitude of about 770 kilometres and flew 3,700 kilometres, according to South Korea's military — far enough to reach the US Pacific territory of Guam.

The missile appeared to follow a similar flightpath to another missile launched on August 29.

The ABC's Rachel Mealey said people in Hokkaido were woken by mobile phone alerts telling them to take cover.

"Obviously a very anxious wait for the Japanese again as they waited to see just what path this missile was going to take," she said.

Australian Kerry Winter, who lives in Sendai, said she received a warning message on her phone about 7:05am (local time).

It was the second time in as many weeks that she had received an alert.

"Last time the message said to go to a strong, sturdy building and evacuate," Ms Winter said.

"It seems there was confusion over that, because people didn't know where to evacuate to. [This time] they changed it and said stay inside. Underground if you can."

Northern attack on US would be 'suicide note': Turnbull

Sorry, this video has expired North Korea attack on US would be a 'suicide note' says Turnbull

Prime Minister Malcolm Turnbull condemned the launch.

"This is another example of why it is vitally important to continue to tighten those economic sanctions on North Korea," Mr Turnbull told journalists in Canberra on Friday morning.

How would Australia defend itself? A Defence Force document warns Australia needs to start thinking about defending itself from a ballistic missile attack, amid the growing threat posed by North Korea. Read more Read more

"The critical thing is to continue to apply economic pressure on North Korea to bring the regime to its senses.

"Nobody wants to see a war on the Korean peninsula. If Kim Jong-un were to start a war, to attack the United States or one of its allies, he would be signing a suicide note that would be the end for his government, and thousands and thousands of people would die.

"It would be a catastrophe.

"And that is why it is vitally important to maintain this economic pressure on North Korea."

Speaking earlier on Sky News, he had called the launch "reckless and criminal".

The North's launch came a day after it threatened to "sink" Japan and reduce the United States to "ashes and darkness" for supporting a UN Security Council resolution imposing new sanctions against it for its September 3 nuclear test.

Two weeks ago, North Korea said it had successfully tested a hydrogen bomb designed to be mounted on its newly developed intercontinental ballistic missile (ICBM), producing a greater yield than any of its previous nuclear tests.

On August 29 a North Korean ballistic missile also flew over Hokkaido island and landed in the Pacific.

Many world leaders have already condemned the latest missile launch. ( Reuters: Kim Hon-ji )

ABC/wires