China's top legislator and a senior North Korean official emphasised opening a "new chapter" of Beijing-Pyongyang relations, the North's state media said Saturday, as they met for one of the most high-level talks between the allies in years.

Beijing's third highest-ranking official Zhao Leji -- a member of the powerful Standing Committee of the Chinese Communist Party's Politburo -- is on a goodwill visit to the nuclear-armed North as the two countries mark 75 years of diplomatic ties.

China is North Korea's most important economic benefactor and diplomatic ally, obstructing US-led efforts at the UN Security Council alongside Russia to impose stricter sanctions on Kim Jong Un's government in response to its increased weapons tests.

Zhao and his North Korean counterpart Choe Ryong Hae attended an opening ceremony for the "year of DPRK-China friendship" in Pyongyang on Friday, North Korea's official Korean Central News Agency said, using the acronym for the North's official name.

In a speech, Zhao said it is the "consistent strategic policy" of Beijing to "successfully defend, consolidate and develop" China-North Korea relations, according to KCNA.

China is willing to "thoroughly implement the important common understanding" of the two countries and "open up a new chapter of China-DPRK friendship along with the times", he added.

North Korea's Choe said the two countries' relationship "has greeted a new heyday under the wise leadership" of their leaders, KCNA said.

Choe and Zhao were seen sitting next to each other watching performances by what KCNA said were "prestigious art troupes" of the two nations at the East Pyongyang Grand Theatre, AFP footage showed.

Some performers wore colourful traditional Korean and Chinese garments, and what appeared to be the final moment of the event highlighted a massive image of the countries' flags, accompanied by the phrase "eternal friendship".

Zhao is China's third highest-ranking official, behind President Xi Jinping and Premier Li Qiang.

Xi last met Kim in 2019 before the onset of the Covid-19 pandemic, making the Pyongyang meeting between Zhao and Choe one of the most high-level meetings in years.

South Korean local media reports said this week that Zhao's trip could include planning for Kim's next potential state visit to Beijing.

North Korea's rhetoric towards the South has been in stark contrast to the friendly relations with Beijing.

This year, Kim has declared Seoul his country's "principal enemy", jettisoned agencies dedicated to reunification and outreach, and threatened war over "even 0.001 mm" of territorial infringement.

China's state-run news agency Xinhua said Friday that Zhao and Choe discussed the "situation on the Korean peninsula", and Zhao expressed Beijing's willingness to "intensify legislative exchanges and cooperation".