Secretary-General Ban Ki-moon strongly urged North Korea on Tuesday to reconsider its decision to launch a rocket which would be "a clear violation" of U.N. sanctions.
The U.N. chief also urged Pyongyang to suspend all activities related to its ballistic missile program, U.N. spokesman Martin Nesirky said.
The U.N. Security Council has imposed two rounds of sanctions on North Korea following its nuclear tests and a 2009 resolution orders the North not to conduct any launch using ballistic missile technology.
"Such a launch would also heighten tension in the region," Ban's spokesman said.
The International Maritime Organization said Monday that North Korea had informed it that it planned to launch a satellite between Dec. 10-22.
It would be North Korea's second launch attempt under leader Kim Jong Un, who took power following his father Kim Jong Il's death nearly a year ago. The embarrassing misfire of its last rocket eight months ago earned the country widespread international condemnation.
The secretary-general also called on the North to reestablish a moratorium on missile launches, as required by the Security Council, Nesirky said.
Ban, a former South Korean foreign minister, renewed his call on North Korean authorities "to work towards building confidence with neighbouring countries and improving the life of its people," he said.
"He reaffirms his commitment to working for peace and stability on the Korean peninsula and helping the people in the DPRK," Nesirky said, using the initials of the country's official name, the Democratic People's Republic of Korea.
The United States considers North Korea's rocket launches to be veiled covers for tests of technology for long-range missiles designed to strike the United States.