The two-day visit by Wang Yi -- the highest-ranking Chinese official to travel to North Korea in years -- follows a landmark inter-Korean summit and precedes a meeting between the North's leader Kim Jong Un and US President Donald Trump in coming weeks.

Beijing "fully backs... (North Korea's) efforts to achieve the goal of denuclearisation on the Korean peninsula," Wang said during talks with his North Korean counterpart Ri Yong Ho, China's official Xinhua news agency reported.

He also said that China was "willing to strengthen communication... (with North Korea) and continue to play a positive role in seeking a political solution to the Korean peninsula issue", Xinhua reported.

The two top diplomats met in Beijing last month, days after Kim travelled to China for talks with President Xi Jinping.

It was Kim's first overseas trip since he took power in 2011 and came amid signs of a diplomatic thaw.

Ri said the talks between Xi and Kim had paved the way for the two countries to develop "friendly relations from a new starting point", Xinhua reported.

He said the regime would "maintain close communications with China on how to realise denuclearisation and establish peace mechanisms on the Korean peninsula, while enhancing dialogue with all parties concerned", according to Xinhua.

Wang, who arrived in Pyongyang on Wednesday, is the first Chinese foreign minister to visit the North since 2007, a lapse that highlights the rough patch in relations between the allies in recent years.

China -- North Korea's sole diplomatic ally and economic benefactor -- has supported a series of United Nations sanctions against the North over its nuclear and missile programmes.

Last year the North staged its most powerful nuclear test to date and launched missiles capable of reaching the US mainland as Kim and Trump traded threats of war and personal insults, sparking global security fears.

Experts say China is now likely eager to avoid being marginalised in the wave of diplomacy that led to last Friday's historic summit between Kim and the South's President Moon Jae-in.

Kim is expected to meet Trump in the coming weeks at a time and place yet to be announced.

The North Korean leader has also invited Xi to visit Pyongyang but no date has been set.