A North Korean satellite launch has ended in failure after the rocket’s second stage malfunctioned, sending the booster and payload plunging into the sea, North Korean state media says.

The new “Chollima-1” satellite launch rocket failed because of instability in the engine and fuel system, state news agency KCNA reported.

Wednesday’s flight was the nuclear-armed state’s sixth satellite launch attempt, and the first since 2016. It was supposed to put North Korea’s first spy satellite in orbit.

It prompted emergency alerts and brief evacuation warnings in parts of South Korea and Japan. The notices were withdrawn with no danger or damage reported.

North Korea had said it would launch its first military reconnaissance satellite between May 31 and June 11 to boost monitoring of US military activities.

South Korea last week placed satellites in orbit with a domestically designed and produced rocket for the first time, and China sent three astronauts to its space station as part of crew rotation on Tuesday.

In data provided to international authorities, North Korea said the launch would carry the rocket south, with stages and other debris expected to fall over the Yellow Sea and into the Pacific Ocean.

Air raid sirens wailed across the South Korean capital of Seoul at 6.32am local time (7.32 AEST) as the city warned citizens to prepare for a potential evacuation. Later alerts said the city warning had been a mistake.

The Japanese government issued an emergency warning over its J-Alert broadcasting system for residents of the southern prefecture of Okinawa to take cover indoors early on Wednesday.

It later said the rocket would not fly into Japanese territory and lifted the warnings.

On Tuesday, Ri Pyong Chol, vice-chairman of the Central Military Commission of North Korea’s ruling Workers’ Party, said ongoing joint military exercises by the US and South Korea required Pyongyang to have the “means capable of gathering information about the military acts of the enemy in real time.”

The White House condemned Wednesday’s launch and said in a statement that it was assessing the situation in co-ordination with allies.

“This claimed space launch involved technologies that are directly related to the (North Korean) intercontinental ballistic missile program,” spokesman for the White House’s National Security Committee, Adam Hodge, said in a statement.

Japan’s Chief Cabinet Secretary Hirokazu Matsuno said North Korea’s rocket disappeared from radar above the Yellow Sea and did not make it into space, and added the government had no further information to share now.

“We strongly condemn North Korea’s actions,” he said.

Tokyo lodged a complaint to Pyongyang through diplomatic channels in Beijing, he said.

UN Secretary-General Antonio Guterres also condemned the satellite launch, a spokesperson said.

He said any launch by Pyongyang using ballistic missile technology was contrary to UN Security Council resolutions.

North Korea has attempted five other satellite launches, with two placed in orbit, including during its last such launch in 2016. Its capacity for constructing working satellites remains unproven, however, analysts say.

“To the best of our knowledge, North Korea has a very limited capacity to build satellites,” said Brian Weeden of the Secure World Foundation, a US-based space policy and security organisation.

“They have launched a couple of satellites before, but all of them failed immediately after launch or shortly thereafter and none of them appeared to have any significant capability.”

– AAP