North Korea's leader Kim Jong Un lauded his country's "international prestige" as celebrations to mark the 80th anniversary of the founding of its ruling party kicked off.

The authoritarian state has rolled out the red carpet for high-ranking officials from ally countries, including Chinese Premier Li Qiang and Russia's former President Dmitry Medvedev.

While it faces "ferocious political and military pressure" from adversaries, North Korea's "international prestige... as a faithful member of the socialist forces" is growing day by day, Kim said on Thursday.

Photographs on state media show a beaming Kim welcoming foreign dignitaries and an evening display of fireworks, among other festivities.

Leaders from other socialist states, such as Vietnam's Communist Party chief To Lam and Laos's President Thongloun Sisoulith are also in North Korea to celebrate the Workers' Party's anniversary.