The republic, virtually the last outpost of Cold War-era communism, vowed to strengthen its armed forces despite acute food shortages and a foundering economy.

"There is no limit to the ideological and mental power of the military and the people united firmly under their leader," said Rodong Sinmun, newspaper of the ruling party.

"We should continue to make utmost efforts to strengthen the military power of our republic," the editorial said, adding that it became a peerless military power with "a strong war deterrent" due to Kim Jong-Il's leadership.

The "war deterrent" is a reference to the nuclear programme which the North promised to shut down after an atomic weapons test in 2006.

But it has halted work to disable its plutonium-producing plants, and says it will start repairing them, following a deadlock in a six-nation disarmament deal.

South Korea's JoongAng Ilbo newspaper, quoting Seoul government sources, said Tuesday's parade would be the biggest ever, given the number of military weapons and equipment being moved to the capital.

"The North probably wants to boost the image of its military might in order to cement unity within the country and secure a better position in the denuclearisation negotiations," one source said.

In addition to the troops and hardware, the newspaper said one million civilians were expected to gather at a rally.

It was unclear whether reclusive leader Kim Jong-Il, 66, would attend.

Chosun Ilbo newspaper, quoting sources in Beijing, said he collapsed last month but added that there did not seem to be a general panic over his health.

At an anniversary ceremony Monday, Premier Kim Yong-Il struck a defiant note, saying tensions were rising on the peninsula due to antagonistic tactics by "US imperialists and their followers."

Pyongyang "will resolutely and mercilessly punish even the smallest behaviour of provocation that infringes upon the sovereignty and interests" of the state, he said.

The North's military numbers some 1.1 million but the country relies on foreign aid to feed millions.

However, the austere capital Pyongyang has been refurbished for the anniversary and decorated with flowers and flags. Slogans extol the virtues of Kim and of his father and founding president Kim Il-Sung, who died in 1994.

"Victory and glory for 60 years," read some.

A 50,000-person performance of acrobatics and gymnastics, entitled "May the Country Prosper," was attended by senior officials including de facto head of state Kim Yong-Nam on Monday.

Tuesday's parade will be closely watched for any sign of the North's more modern missiles. It test-fired a Taepodong-1 long-range missile in 1998.

In July 2006 it test-fired seven missiles including a more advanced Taepodong-2, which exploded soon after lift-off but which could in theory reach parts of the United States.

Nuclear disarmament work has halted because of a dispute between the North and its negotiating partners about ways to verify the nuclear inventory it handed over in June.

Washington has refused to remove the North from a terrorism blacklist until agreement on verification is reached.

After the defeat of Japanese colonisers in World War II, the Korean peninsula was divided into Soviet and US zones of influence. North and South Korea came into being in 1948.