Japan put its ballistic missile defences on alert on Monday and warned that it would shoot down any projectile that threatened its territory after North Korea notified Japan of a satellite launch between May 31 and June 11.
North Korea says it has completed its first military spy satellite and leader Kim Jong Un has approved final preparations for the launch.
Analysts say the satellite is part of a surveillance technology programme, that includes drones, aimed at improving nuclear-armed North Korea's ability to strike targets in the event of war.
"We will take destructive measures against ballistic and other missiles that are confirmed to land in our territory," Japan's defence ministry said in a statement.
The ministry said it would use its Standard Missile-3 (SM-3) or Patriot Missile PAC-3 to destroy a North Korea missile.
Japanese Prime Minister Fumio Kishida told reporters that any North Korean missile launch would be a serious violation of U.N. Security Council resolutions condemning its nuclear and missile activity.
"We strongly urge North Korea to refrain from launching," his office said in a post on Twitter, adding it would cooperate with its U.S. ally, South Korea and other countries, and would do all it could to collect and analyse information from any launch.
South Korea joined Japan in calling for North Korea to scrap the planned satellite launch.
"We urge North Korea to withdraw the illegal plan to launch immediately. If North Korea presses ahead, it will pay the price and suffer," a spokesperson for South Korea's foreign ministry said in a statement.
Reclusive North Korea has conducted a series of missile launches and weapons tests in recent months, including a new, solid-fuel intercontinental ballistic missile.
Its leader, Kim, in May inspected a military satellite facility, the North's KCNA state news agency reported.
North Korea has tried several times to launch "earth observation" satellites, of which two appeared to have been successfully placed in orbit, the latest in 2016.
Japan in April dispatched to the East China Sea a destroyer carrying the SM-3 interceptors that can hit targets in space, and sent ground-based PAC-3 missiles, designed to strike warheads closer to the ground, to the Okinawan islands.
Japan expects North Korea to fire the rocket carrying its satellite over the southwest island chain as it did in 2016, a defence ministry spokesperson said.
"The government recognises that there is a possibility that the satellite may pass through our country's territory," Japan's chief cabinet secretary, Hirokazu Matsuno, told a regular briefing after North Korea informed the Japanese coast guard of the planned launch.
North Korean state media has criticised plans by its rivals, South Korea, the United States and Japan, to share real-time data on its missile launches, describing the three as discussing "sinister measures" for tightening military cooperation. (Reporting by Hyunsu Yim in Seoul and Nobuhiro Kubo, Elaine Lies, Satoshi Sugiyama and Tim Kelly in Tokyo; additional reporting by Ju-min Park in Seoul and David Dolan in Tokyo; Editing by Robert Birsel)