North Korea's rocket launch is a timely boost for its young leader, securing his year-old grip on power and laying to rest the humiliation of a much-hyped but failed launch eight months ago, analysts say.

While Wednesday's launch is likely to deepen the international isolation of a country already in dire economic straits, its real and symbolic value can only strengthen Kim Jong-Un's hand.

The timing was especially significant, both domestically and overseas where the launch poses a particular challenge for concerned neighbours China, Japan and South Korea -- all in a period of political transition.

At home it lent crucial validity to Kim's place in the country's dynastic succession, coming days before the first anniversary of the death of his father, Kim Jong-Il and in the centennial birth year of his grandfather and the communist North's founder, Kim Il-Sung.

"The launch means the fulfilment of Kim Jong-Il's last wish," said Yoo Ho-Yeol, a political science professor at Korea University in Seoul.

"As such, it helps cement Jong-Un's grip on power and strengthens his authority over the North's military elites, securing their loyalty and a sense of solidarity under his leadership," Yoo said.

By pushing ahead with the launch, Kim, who is not yet 30, has proved he is willing to follow his father's example in flouting UN resolutions and ignoring the advice and concerns of his only major allies in Beijing.

"If anything, they carried out this test knowing what they were going to get in terms of criticism and condemnation and potentially an increase of sanctions," said James Schoff, a senior associate at the Carnegie Endowment for International Peace.

"But they're betting that it won't be that bad and it will be a success on the domestic front," Schoff said. "And it's a sort of vindication for the April failure."

The April launch, for which Pyongyang had taken the unprecedented step of inviting the foreign media, was seen as a personal humiliation for Kim Jong-Un with the carrier exploding shortly after take-off.

The opaque, highly secretive world of North Korea's political elite has always been difficult to decipher, making judgements about the power and stability of its leadership speculative at best.

After Kim Jong-Il's death on December 17, numerous experts had suggested that his son was too young and inexperienced to command genuine loyalty and some had gone so far as to forecast the country's imminent collapse.

One year on, both North Korea and Kim Jong-Un are still there and the new leader has apparently shored up his power base with a series of high-level personnel changes in the military and party leadership.

"You still can't say Kim Jong-Un's leadership is fully in control. But the launch will at least offer a symbolic platform to further strengthen his position," said Ham Hyeong-Pil from the Korea Institute for Defense Analyses.

But several analysts stressed that any sense of national pride and solidarity triggered by the rocket launch would be short-lived given the grim realities of the impoverished North's economic situation.

"It's a short-term boost, but long term, it's probably not that helpful," said Gordon Flake, the executive director of the Mansfield Foundation who advised President Barack Obama on Korea policy during his first White House race.

"It probably helps him with the military. I don't know if it solves any underlying problems that he's facing. In fact, when you're talking about food or economic development or opening, it puts them in a further constrained position," Flake said.

In recent months, there have been unconfirmed reports in the South Korean media of instances of civic unrest in the North, and experts have noted recent hardline speeches by Kim urging the security and judicial authorities to crack down on dissent.

With the UN Security Council now discussing a toughening of sanctions against Pyongyang, North Korea's international isolation is likely to deepen in the months and year ahead.

"But over the long term, when the dust settles down, North Korea and the United States will find no other alternative but to seek dialogue," said Kim Yong-Hyun, a professor at Dongguk University.

In both 2006 and 2009, the North followed long-range missile launches with a nuclear test, but Kim said Pyongyang would probably opt to keep a low profile for a while.

"I don't see it moving on to a third nuclear test. Instead, it will take a breather," he said.