"Such an act would undermine recent positive diplomatic progress and, in its effect on international donors, would likely worsen the humanitarian situation inside the country," he said in a speech in Singapore.

Ban told an audience of government officials, diplomats and academics that he was "very troubled and very deeply concerned" by Pyongyang's announcement to launch a satellite next month.

He said it would be a "clear violation" of UN Security Council resolutions and warned that the North already had a "serious humanitarian crisis" on its hands.

Nuclear-armed North Korea has said it will launch a rocket in April to put a satellite into orbit, a move which the United States and its allies see as a pretext for a long-range missile test.

Washington voiced doubt last week over whether it could provide food aid to Pyongyang if it followed through on its threat to launch the rocket.

On February 29 the United States said it would move ahead on a plan to deliver 240,000 metric tons of food aid to Pyongyang after North Korea agreed to a partial freeze on its nuclear programme, to suspend missile tests and allow UN inspectors.