"The nuclear issue on the Korean Peninsula is not something that should be discussed at the United Nations," the state-run KCNA news agency said.
North Korea "would not recognize and pronounce null any resolution or document on the nuclear issue," said KCNA, monitored by South Korea's Yonhap news agency.
The Security Council is due to discuss the nuclear dispute on Wednesday. North Korea rejects U.N. involvement in the standoff, saying the North's dispute is only with the United States. Pyongyang demands direct talks with Washington.
"The U.N. seems to have lost its mandate because of the U.S. invasion of Iraq," KCNA said. "It is ridiculous for the (Security Council) to talk about handling the (North Korean) nuclear issue."
Washington, which wants multilateral talks, has been pressing the council to adopt a statement condemning Pyongyang for failing to meet its obligations to prevent the spread of nuclear arms.
China, which has ties with the reclusive North Korean regime and is one of the five veto-wielding members of the council, has refused to even discuss such a statement.
The 15-member council could eventually discuss imposing sanctions against North Korea if a political solution is not found
a move the North has warned it would regard as a declaration of war.
But both China and Russia, which is also a permanent council member, have said they oppose international sanctions. The other council members with veto power are the United States, Britain and France.
The nuclear standoff flared in October when U.S. officials said North Korea admitted having a secret nuclear program in violation of a 1994 agreement. As punishment, Washington and its allies suspended oil shipments promised under the deal.
North Korea retaliated by taking steps to reactivate frozen nuclear facilities capable of making nuclear bombs and withdrawing from the Nuclear Non-Proliferation Treaty. It also deported U.N. personnel who had been monitoring its nuclear facilities.
For weeks, North Korea has claimed that the United States planned to attack it after Iraq. Washington says it seeks a diplomatic end, but has not ruled out a military solution.
Last year, President Bush said North Korea was part of an "axis of evil" along with Iraq and Iran, and that it was developing weapons of mass destruction.
On Friday, Bush called South Korean President Roh Moo-hyun to pledge continued cooperation in resolving the nuclear standoff.
"The two leaders reiterated their intention to resolve the North Korean nuclear issue peacefully and pledged to continue their close consultation," White House press secretary Ari Fleischer said.
Also Friday, Roh's national security adviser Ra Jong-yil said both Russia and China had indicated they would work toward a peaceful solution to the North Korean nuclear issue.
Ra visited Moscow and Beijing this week.
Meanwhile, 15 ruling and opposition lawmakers of South Korea suggested on Friday that Seoul consider economic sanctions against Pyongyang.
The proposal came as North Korea showed no indications that it would attend Cabinet-level talks with South Korea, scheduled to begin in Pyongyang on Monday.
South Korean officials had hoped to use the talks to try to persuade North Korea to give up its nuclear ambitions in return for aid and better ties with the outside world.
By JAE-SUK YOO