UN Secretary-General Ban Ki-moon said Thursday he would raise North Korea's planned rocket launch at a Seoul nuclear summit next week, expressing "deep concern" over the issue.

"I am going to discuss the issue with the president of the Republic of (South Korea) in Seoul and I will also engage with other leaders attending the nuclear summit," Ban told a press conference in Malaysia.

The nuclear-armed North has announced it will launch a rocket next month to put a satellite into orbit, a move which the US and its allies see as a pretext for a long-range missile test.

Pyongyang has said any South Korean attempt to address the North's nuclear programme at the March 26-27 Seoul summit would be seen as a declaration of war.

But the programme and the rocket launch were expected to be hot topics on the sidelines of the meeting, which will see US President Barack Obama and other world leaders meet to discuss nuclear security issues.

A UN Security Council resolution passed after the North staged missile and nuclear tests in 2009 bans a ballistic missile launch for any purpose.

"As secretary-general of the United Nations I express my deep concern by the announcement of the government of the DPRK (on) their intention to launch a satellite," Ban said, using the acronym for North Korea's official name.

Ban, a South Korean, also called the planned launch "a clear violation" of Security Council resolutions and said it "threatens the peace and security on the Korean peninsula".

He said it could also undermine recent positive signs on long-running international efforts to end North Korea's nuclear programme.

Under a deal announced last month but now in jeopardy, Washington would offer substantial food aid for a partial nuclear freeze. It has raised modest hopes of progress in the denuclearisation efforts.

"This (the rocket launch) is again undermining the positive atmosphere which has been established recently between the US and the DPRK," Ban said.

The North has lambasted next week's meeting -- the South's biggest-ever diplomatic gathering -- as an "unsavoury burlesque" intended to justify an atomic attack by South Korea and its US ally.

Despite Pyongyang's threats, leaders of five nations will discuss ways to press North Korea to scrap the rocket launch, South Korean President Lee Myung-Bak was quoted saying Wednesday.

The United States, China, South Korea, Japan and Russia have been involved since 2003 in talks to shut down the North's nuclear programme.

The talks have been broken off repeatedly over various instances of North Korean brinksmanship.

North Korea's state news agency said Wednesday any attempt by Lee to raise the issue would be "a ridiculous attempt and an absolutely unpardonable criminal act."

"Any provocative act would be considered as a declaration of war against us and its consequences would serve as great obstacles to talks on the denuclearisation of the Korean peninsula," it said.