Kim hails nuke power status

Kim Jong-Un opened North Korea's first ruling party congress for nearly 40 years yesterday, with a defiant defence of the "magnificent" strides made in the country's nuclear weapons programme.

Hailing the historic test of what North Korea claims was a hydrogen bomb in January, the isolated state's young leader said it had shown the world it would not be cowed by sanctions or outside pressure.

Dressed in a western style suit and tie, Kim's speech was delivered to thousands of party delegates who had gathered in Pyongyang for the once-in-a-generation conclave.

In particular, he praised the country's scientists for "creating milestone miracles with the magnificent and exhilarating sound of the first H-bomb of our republic".

The test, which was followed a month later by a successful long-range rocket launch, "clearly demonstrated to the whole world our undefeatable spirit and endless power ... in defiance of malicious pressure and sanctions by enemy forces", he said.

Most experts have questioned the North's H-bomb claim, saying the detected yield from the January test was far too low for a full-fledged thermonuclear device.

There has been widespread speculation about the North preparing another nuclear test to coincide with the congress, as a defiant gesture of strength and future intent.

The 33-year-old Kim, who was not even born when the last Workers' Party Congress was held in 1980, said the party conclave would prove to be a "new milestone" that would lay out the future direction "of our revolutionary march".

While the agenda -- and even the duration -- of the congress remains unknown, its main objective is clearly to confirm Kim Jong-Un's status as absolute ruler and the legitimate inheritor of the Kim family's dynastic rule which spans almost seven decades.

It may also enshrine as formal party doctrine Kim's "byungjin" policy of pursuing nuclear weapons in tandem with economic development.

Analysts will be watching for personnel changes as Kim looks to bring in a younger generation of leaders hand-picked for their loyalty.

Around 130 foreign journalists were invited to cover the event, but were not allowed inside the congress venue, restricted instead to watching from a spot 200 metres away in the light drizzle falling on the capital.

Notably absent was any Chinese representation -- a possible reflection of the increasingly strained ties between the North and its sole major ally.

Since Kim took power after the death of his father in December 2011. Since then, he has demonstrated a ruthless streak, purging the party, government and powerful military of those seen as disloyal.