North Korean leader Kim Jong-un is likely to use next week's party congress as an occasion to reaffirm his unfettered power at a time when the isolated country is struggling to tackle tougher U.N. sanctions, experts predicted.

North Korea said Wednesday that the Workers' Party of Korea will open its first congress in more than three decades next Friday. Seoul's unification ministry expected the event to run for four to five days.

It will be the first party congress since October 1980 and also the first under the regime of leader Kim who assumed power in late 2011 following the sudden death of his father Kim Jong-il.

The party congress, the highest-level political guidance body, comes amid nagging concerns about advances in North Korea's nuclear and missile development programs.

Analysts said that the upcoming event will serve as a venue to highlight Kim's one-man leadership, reshuffle top officials and unveil his visions for the defense and economic sectors.

"More than reaffirming his grip on power, it will serve as a coronation of the Kim Jong-un era," said Ken Gause, a senior analyst on North Korea at CNA Corp. in the United States.

North Korea has intensified the personality cult of the current leader since its January nuclear test and a long-range rocket launch the following month. Kim is believed to have strengthened his reign of terror by executing more than 100 officials to take a firm grip on power.

The congress is widely expected to entail a major reshuffle of top officials, which may include the country's ceremonial leader Kim Yong-nam, experts said.

"The congress will lay the groundwork for Kim Jong-un to prove his legitimacy as the sole leader," said Yang Moo-jin, a professor at the University of North Korean Studies.

The party congress comes amid high tensions as Pyongyang is threatening to conduct another nuclear test and launch another long-range missile in defiance of stronger U.N. sanctions.

In March, the U.N. Security Council slapped tougher sanctions on North Korea as punishment for its nuclear test and long-range rocket launch earlier this year.

Since last month, Pyongyang has fired off projectiles and ballistic missiles, warning that it is ready to wage nuclear strikes against Seoul and Washington.

Experts said that at the congress, the North's leader is expected to defend his signature policy of developing nuclear weapons in tandem with boosting its moribund economy, commonly known as the "byeongjin" policy.

Kim did not make a reference to his dual-track policy during his New Year's message on Jan. 1, but just five days later the North conducted its fourth nuclear test.

"There is a possibility that North Korea could adjust or refine the byeongjin policy," said Kim Yong-hyun, a professor of North Korean studies at Dongguk University.

There is growing speculation that North Korea could carry out a fifth nuclear test ahead of the party congress. Seoul and Washington have warned of stronger sanctions if the North makes additional provocations.

"I think there is a good chance for additional weapons demonstrations," Gause said, adding that the North's leader needs his "bona fides" as a national security leader.

"Since the failure of his diplomacy campaign has made it impossible for him to show progress on the economy, he has no choice but to demonstrate to the country that he can keep it safe by ensuring its deterrent," he said.

Touching on the economy, experts said that the North is likely to unveil new economic policies at the congress in a bid to flesh out the leader's plan to boost the country's fragile economy.

Since Kim inherited power in late 2011, the North's economy has posted marginal growth with its marketplaces noticeably expanding.

North Korea's economy is estimated to have grown 1 percent in 2014, similar to a 1.1 percent on-year gain the previous year, according to South Korea's central bank. It posted economic growth for the fourth straight year in 2014 after contracting in 2009 and 2010.

In 2012, the North announced the so-called "6.28 measures" that centered on allowing farmers to keep 30 percent of their production quota plus any excess over the quota. In 2014, it unveiled a new set of reforms that call for raising the farmers' portion to 60 percent.

"As the North has claimed its success in producing achievements on the fronts of ideology, politics and the military for a strong and thriving nation, it will focus on propping up the economy," said Kim Young-hee, an expert on the North Korean economy at Korea Development Bank.

But a Seoul government official said if the sanctions are put in place for a long time, the North's economy is not likely to recover due to a shortage of dollars and products. 

Meanwhile, analysts shared mixed views about whether or not the North will launch a charm offensive toward Seoul after the party congress.

Cheong Seong-chang, a senior researcher at the Sejong Institute, said that there is a low chance that the North would make a conciliatory gesture toward South Korea amid standoffs sparked by the North's nuke and missile provocations.

The Seoul government said the North could propose bilateral talks with the United States including talks about a peace treaty.

North Korea has recently called for talks about a peace treaty with Washington to formally end the 1950-53 Korean War. The conflict ended in an armistice leaving the two Koreas technically locked in a state of war.

But Seoul and Washington have dismissed the idea as a ploy to divert attention away from the North's nuclear aspirations. (Yonhap)