The Japanese government said on Saturday that North Korea had launched the rocket but later retracted the news, blaming a faulty detection device for the erroneous information.
The launch, which North Korea had earlier said was scheduled for some time between April 4 and April 8, has sparked alarm because Pyonyang has acknowledged it has nuclear weapons.
Wayne Hay, Al Jazeera's correspondent in Seoul, the South Korean capital, said that Japan is particularly concerned about the planned launch.
"They have been one that really have been putting all the plans in place, in terms of military hardware. They have really been on edge. They have plenty of land-to-air batteries in place around Tokyo and other parts of the country.
"The rocket [if it is fired] will fly over Japense territory so they have a right to be nervous. The North Koreans have assured Tokyo that the launch is for peaceful purposes but the Japanese are fearful."
Washington, Seoul and Tokyo suspect North Korea's real motive in the launch is to test its long-range missile technology.
The US, Japan and South Korea have all deployed warships with radar and other surveillance equipment in the waters near North Korea ahead of the launch.
On Friday, Barack Obama, the US president, warned of international action against North Korea if it goes ahead with the launch.
"Should North Korea decide to take this action, we will work with all interested partners in the international community to take appropriate steps to let North Korea know that they cannot threaten the safety and stability of other countries with impunity," Obama said.
Pyongyang has said that the rocket is carrying a satellite as part of a peaceful space programme.
But the South Korean and Japanese governments allege that North Korea is using the launch to test its Taepodong-2 long-range missile, which is capable of reaching the US.
Pyongyang fired a Taepodong-2 in a July 2006 test session but it exploded shortly after launch. It conducted a nuclear weapons test, its only one to date, in October 2006.
The US, South Korea and Japan say another rocket launch by North Korea will violate UN resolutions banning further ballistic missile tests.
But China, which has a veto in the UN Security Council and which has close ties to Pyongyang, is likely to oppose fresh sanctions, as well as the tightening of existing ones against North Korea.
Japan, South Korea and the US have said they do not intend to shoot down the rocket unless it heads towards their respective territories.
North Korea has said that any attempt to destroy the missile will be considered an act of war and that it could restart a plant making arms-grade plutonium if the UN imposes fresh restrictions.