A senior United States official warns that North Korea's latest planned missile test launch will be aimed towards South-East Asia and Australia for the first time.
Kurt Campbell, the US assistant secretary of state for East Asian and Pacific affairs, delivered the message in person to Australian Foreign Minister Bob Carr.
Mr Campbell says if the missile test proceeds, analysts predict it is likely to impact in an area roughly between Australia, Indonesia and the Philippines.
Australia's Department of Foreign Affairs and Trade says it is deeply concerned by North Korea's plans.
North Korea is also planning to launch a rocket next month to put a satellite into orbit, a move the US and Australia see as a pretext for a long-range missile test.
United Nations Secretary General Ban Ki Moon has urged North Korea to reconsider its satellite plan and has agreed with South Korean President Lee Myung Bak and that the rocket launch would be a "serious provocation" in defiance of UN Security Council resolutions, the presidential office said in a statement.
North Korea says it will launch the observation satellite, the Kwangmyongsong-3, borne by the Unha-3 rocket, between 12 and 16 April to mark the centenary of the birth of the nation's founder, Kim Il Sung, on 15 April.
Official media in North Korea say that the country's legislature will meet on 13 April to formally approve the handover of power from the late ruler, Kim Jong Il, to his son, Kim Jong Un.
Analysts are expected to pay close attention to whether the son will be made chairman of North Korea's National Defence Commission, a position that would formally make him supreme commander.
Mr Kim took power in December after his father Kim Jong-il died and experts say he could also be named secretary general of the nation's political party.
In South Korea, talks between leaders on the sidelines of next week's Nuclear Security Summit in Seoul are expected to canvass concerns that the satellite launch will provide a cover for testing a long-range ballistic missile that could later be used to deliver nuclear warheads.
Japan has ordered its air force to prepare for activation of its missile defence system, to destroy any North Korean rocket that passes through the country's airspace.