North Korea's planned rocket launch could happen as early as today, defying calls from around the world for the country to abandon the launch.

The rocket launch window opened at 8:00am (AEST), with North Korea saying Monday is the last opportunity to launch the three-stage rocket.

The rocket's flight path will take it south past the Philippines and over central Australia.

The United States and its allies have denounced the launch as a disguised ballistic missile test.

But Pyongyang says the rocket will transport a peaceful observation satellite into orbit, with the regime warning it will mercilessly punish any nation that interferes with the launch.

"We don't really care about the opinions from the outside," said Paek Chang-ho, the head of the satellite control centre at the Korean Committee of Space Technology.

"This is critical in order to develop our national economy."

Weather conditions on the Korean peninsula appear to favour a launch either today or Saturday, according to meteorological reports from Japanese television.

The US and Japan have vowed to take action in the UN Security Council if the launch goes ahead.

Saying a launch would be "provocative", White House spokesman Jay Carney reiterated that "this kind of blatant disregard for their commitments makes it impossible" for the US to go ahead with a food aid deal with North Korea.

"We will have a response obviously if the North Koreans take this action. And I mean a verbal response," Mr Carney told reporters in Washington, seeming to dismiss any prospects for US military action.

Destabilising

Japan and South Korea are threatening to fire at any debris which may fall towards their territory.

South Korea warns the launch could be a precursor to another underground nuclear test by the communist North.

Seoul says satellite pictures suggest work is underway at North Korea's nuclear test site.

Australian Foreign Minister Bob Carr says the launch is likely to be hugely destabilising for the region.

Senator Carr says he is deeply worried about North Korea's actions.

"They have acted in the past in defiance of world opinion driven by those forces, the dictatorship, the suppression of their people, their starving people and their nationalism," he said.

"And all indications are these factors will again produce some behaviour by them that's hugely destabilising and worrying to the region."

Sorry, this video has expired Analyst says N Korea has tested rockets before

ABC/Reuters