Since a failed summit with the United States in 2019, North Korea has repeatedly said it will never give up its nuclear weapons and declared itself an "irreversible" nuclear state.

While visiting weapons research facilities this week, Kim said Pyongyang "would put forward the policy of simultaneously pushing forward the building of nuclear forces and conventional armed forces", according to the state-run Korean Central News Agency.

Kim also emphasised the need to "modernise" the country's conventional armed forces, without specifying the date of the party meeting.

The North Korean leader has been emboldened by the war in Ukraine, securing critical support from Russia after sending thousands of North Korean troops to fight alongside Moscow.

Moscow and Pyongyang signed a mutual defence pact last year when Russian President Vladimir Putin visited the reclusive state.

Seoul has repeatedly warned that Russia is stepping up support for Pyongyang, including the potential transfer of sensitive Russian military technology, in return for North Korea's assistance in fighting Ukraine.

"In essence, it reflects (Kim's) view that nuclear forces alone have limits as a deterrent, and that Pyongyang is seeking to boost its war-fighting capability by modernizing its conventional arsenal," Hong Min, a senior analyst at the Korea Institute for National Unification, told AFP.

"North Korea's military technology cooperation with Russia seems to be also expanding into the conventional arms sector, and modernisation plans tailored to 'modern warfare' are likely to be laid out as a mid- to long-term agenda" at the upcoming meeting, he added.

At the last party congress in January 2021, Kim unveiled an ambitious military agenda, pledging to develop advanced weapons such as military spy satellites and solid-fuel intercontinental ballistic missiles.

Analysts say they expect the upcoming meeting to be held early next year.

Kim and Putin flanked China's President Xi Jinping at a massive parade in Beijing this month, drawing an acidic response from US President Donald Trump, who accused the three leaders of plotting against the United States.