North Korea on Saturday said it was actively pursuing a space programme, amid reports from US and South Korean officials that Pyongyang is preparing to test fire a long-range missile.

Rodong Sinmun, the official daily of the ruling communist party, said the North had every right to develop a space programme, as a member of the international community.

"The DPRK's (North Korea) policy of advancing to space for peaceful purposes is a justifiable aim that fits the global trend of the times. There is no power in the world that can stop it," the newspaper said in an editorial.

"As long as developing and using space are aimed at peaceful purposes and such efforts contribute to enhancing human beings' happiness, no one in the world can find fault with them," the paper said.

It noted that Iran on Monday successfully launched a satellite carried by a home-built rocket, setting alarm bells ringing among Western powers because of the implications for the range of its ballistic missiles.

Rodong said North Korea had long been working on space research and development.

"Currently, our scientists and engineers, in keeping with the international trend, are actively pushing ahead with projects aimed at utilising space for peaceful goals," it added.

Officials in Seoul and Washington say there are signs the communist state is preparing to test its Taepodong-2 missile, which has a range of 6,700 kilometres (4,100 miles) and could theoretically reach Alaska.

The missile was initially launched in 2006 but failed after 40 seconds, according to US officials.

A Seoul government source told Yonhap news agency that a missile recently spotted by satellite photographs was believed to be a modified Taepodong-2.

The reports come amid rising tensions between Pyongyang and Seoul and stalled six-nation talks aimed at ending North Korea's nuclear programmes.

Experts disagree on whether the impoverished communist state is technically capable of fitting a nuclear warhead to a missile.