The New Year's Day firing reported by the Yonhap news agency was the second in as many days.

It came from the Yongseong area of the capital Pyongyang and landed in the East Sea, also known as the Sea of Japan, Yonhap said, quoting the Joint Chiefs of Staff.

Military tensions on the Korean peninsula rose sharply in 2022 as the North conducted sanctions-busting weapons tests nearly every month, including firing its most advanced intercontinental ballistic missile ever.

The Joint Chiefs of Staff said it detected the latest launch at 2:50 am (1750 GMT Saturday) and that the missile flew some 400 kilometers (250 miles) before splashing into the sea.

"Our military will maintain a solid readiness posture based on capabilities to respond overwhelmingly to any North Korean provocations," the JCS said in a text message sent to reporters, according to Yonhap.

On Saturday the North fired three short-range ballistic missiles, Seoul's military said, a day after South Korea successfully tested a solid-fuel space launch vehicle.

That North Korean launch also followed the incursion of five North Korean drones into the South's airspace earlier in the week.

Monday's North Korean drone incursion was the first such incident in five years and prompted an apology from Seoul's defence minister after the military failed to shoot down a single drone despite scrambling jets for a five-hour operation.

South Korean president Yoon Suk-yeol called the incident "intolerable" and added that the South should ensure that Pyongyang realised that "provocations are always met with harsh consequences".

Seoul's military staged drills Thursday that the country's top brass said would improve its defences against any future drone provocations.

And on Friday, South Korea successfully tested a new space launch vehicle as part of its drive to strengthen space-based reconnaissance and surveillance capabilities, the defence ministry said.

Pyongyang earlier this month said it conducted an "important final-stage" test for the development of a reconnaissance satellite, claiming it had developed advanced technologies to take images from space.

"The purpose of North Korea's missile launch today is to respond to Seoul's solid-fuelled space launch vehicle. Pyongyang seems to be thinking of this as a competition," Yang Moo-jin, a professor at the University of North Korean Studies in Seoul, told AFP on Saturday.

North Korea is currently holding a major party meeting in Pyongyang at which leader Kim Jong Un and other senior party officials are outlining their policy goals for 2023 in key areas including diplomacy, security and the economy.

Earlier this year Kim said he wanted his country to have the world's most powerful nuclear force and declared the North an "irreversible" nuclear state.

On Wednesday, Kim set out "new key goals" for the country's military, state media reported, without giving any specifics.

North Korea's end-of-year plenary meetings are typically used by the regime to unveil the country's domestic and foreign policy priorities for the year ahead.

Full details of the current session are expected to be announced after it concludes.