North Korea will launch a satellite mounted on a rocket to mark the 100th birthday of its late former President Kim Il-sung, state media reported.
It will take place between 12 and 16 April, a spokesman for the Korean Committee for Space Technology said.
South Korea said the launch would be a "grave provocation" and Japan urged the North to "exercise restraint".
The move is seen as violating UN Security Council resolutions passed after a similar launch in 2009.
Japan is particularly concerned as North Korea's April 2009 rocket was launched over the country.
'Threat to peace'
The country's chief cabinet secretary, Osamu Fujimura, told a news conference on Friday that Japan had set up a crisis management taskforce to monitor the situation and was co-operating with the US and South Korea.
"We believe a launch would be a move to interfere with our effort toward a dialogue, and we strongly urge North Korea not to carry out a satellite launch," he said.
South Korea's foreign ministry said such a move would be a "clear violation" of UN Security Council Resolutions.
"It would be a grave provocation threatening the peace and security of the Korean peninsula and north-east Asia," the ministry said in a statement.
Last month, Pyongyang agreed to suspend long-range missile tests.
The agreement was part of a deal for the United States to supply 240,000 tonnes of food aid to North Korea.
In the launch three years ago, Pyongyang said the satellite made it into orbit and characterised it as a test of its satellite technology.
The move drew condemnation from the US and South Korea and led to the UN resolutions prohibiting the North from nuclear and ballistic missile activity.
Foreign officials said there were no indications that a satellite had reached space and that the launch was a cover for Pyongyang to test long-range missile technology.
The launch next month of a ''working satellite'', the Kwangmyongsong-3, is an opportunity for ''putting the country's technology of space use for peaceful purposes on a higher stage'', said a North Korean spokesman.
The rocket would be launched from the Solace Satellite Launching Station in Cholsan county, North Pyongan province on the country's west coast.
State media also reported that the North has already launched two experimental satellites.