Leaders of five nations will discuss ways to press North Korea to scrap a planned rocket launch when they meet next week at a Seoul summit, South Korea's president said in interviews published Wednesday.

US President Barack Obama will attend the nuclear security summit, along with leaders of China, South Korea, Japan and Russia. All the countries have been involved since 2003 in talks to shut down the North's nuclear programme.

"The North's move to launch the so-called satellite has created a new topic of discussions at the summit, and it's an urgent timing," President Lee Myung-Bak said ahead of the talks to be held Monday and Tuesday.

"The five nations share similar views on this," Lee was quoted as saying. "The best option is for the five nations to try to persuade North Korea to cancel the plan."

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.

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

Washington also says a launch would breach a bilateral deal announced on February 29, which offered 240,000 tonnes of US food aid in return for a partial nuclear freeze and a suspension of missile tests.

"No matter what the North's excuse is, the launch is a clear breach of United Nations Security Council Resolution 1874," Lee told the International Herald Tribune (IHT), South Korea's JoongAng Ilbo newspaper and other media.

"It is breaking a promise with all the countries around the world."

The US-North Korean deal had raised hopes of eased tensions under the North's young new leader Kim Jong-Un.

"We had high expectations, but now we have this happening," Lee said.

"Although we cannot say conclusively, this new development will have a great impact on the assessment of the North, particularly in trust."

The South Korean leader said the launch may bring the North "some domestic political gains, but its loss in the international community will be big".

The South's Unification Minister Yu Woo-Ik called the launch provocative and a senseless waste of money.

"I can't help expressing my regret for such senseless action by the North's regime to go ahead with an immensely costly long-range rocket launch while its people cross the border because of political repression and hunger, to become fugitives in foreign countries," Yu told a forum.

The Seoul summit will focus on ways to keep nuclear weapons material out of the hands of international terrorists and how to shrink stockpiles of plutonium and highly enriched uranium.

It was expected to produce an agreement to reduce the materials by an amount sufficient to make about 20,000 nuclear weapons, the IHT quoted Lee as saying.

"What threatens world peace and security the most is nuclear terrorism," he said.