North Korea expressed willingness Wednesday to rejoin long-stalled nuclear talks, China's foreign ministry announced, the second time in a month Pyongyang has told Beijing it is ready for such dialogue.

North Korean first vice foreign minister Kim Kye-Gwan made the remarks during a meeting in Beijing with Chinese vice foreign minister Zhang Yesui, the ministry said in a statement on its website.

Kim said that North Korea is willing to engage in any form of dialogue to peacefully resolve the nuclear issue, according to the statement.

That included six-party talks, Kim said, referring to a long-stalled process that began in 2003 but has been dormant since late 2008. The statement, however, offered no concrete details.

The six-nation forum, which also includes China, South Korea, Japan, Russia and the United States, is aimed at persuading Pyongyang to abandon its nuclear weapons programme in return for aid and security guarantees.

Kim long served as his country's chief international nuclear negotiator. The meeting Wednesday was billed as a "strategic dialogue" between the Chinese and North Korean foreign ministries.

It follows a meeting late last month in Beijing between Chinese President Xi Jinping and North Korean special envoy Choe Ryong-Hae, a close confidant of the North's leader Kim Jong-Un. Choe had made similar comments.

Tensions over the North's nuclear programme soared earlier this year after the country carried out its third underground atomic test blast in February, angering the international community and resulting in tightened UN sanctions supported by China.

Tensions have waned in recent months, however, amid expectations Pyongyang may be moving towards dialogue rather than confrontation.

But North Korea unexpectedly cancelled much-anticipated talks with South Korea last week, casting some doubt on its intentions.

Shortly after, the North called for high-level dialogue with the US, which welcomed the proposal but said Pyongyang must first curb its nuclear programme.

US President Barack Obama, who met Xi in California earlier this month, said this week that China is taking a tougher line against North Korea's nuclear programme, hailing Xi for taking more responsibility in the world.

Chinese foreign minister Wang Yi and US Secretary of State John Kerry discussed the Korean peninsula in a phone call Wednesday, with Wang calling the Xi-Obama summit a success, the official Xinhua news agency reported.

Next week, Xi is due to hold talks in Beijing with new South Korean President Park Geun-Hye.

North Korea's stated desire for dialogue is in stark contrast to earlier this year, when it carried out a periodic bout of angry and threatening rhetoric, including vowing nuclear missile strikes on the US.

Also Wednesday, Xi and UN chief Ban Ki-moon met in the Chinese capital, discussing the Korean peninsula, Syria and other issues, Ban's spokesman and state media said.

"The secretary-general thanked the president for China's crucial role in helping to reduce tensions on the Korean Peninsula and for supporting a political solution to the conflict in Syria," Martin Nesirky, Ban's spokesman, said in a statement.

China, a permanent member of the UN Security Council, has come under increasing pressure to persuade North Korea to halt its nuclear development.

China, the North's sole ally, is seen as the country with the most influence on Pyongyang's actions.

While China has consistently called for Pyongyang's denuclearisation and has joined in UN sanctions, Beijing has also long helped prop it up with aid and investment.

The China News Service, a state media outlet, reported that Xi described China's "principled positions" on the Korean peninsula and Syria, the report said, without elaborating.

Xi also told Ban that Beijing will increase efforts to promote the peaceful settlement of international disputes, Xinhua reported.

On Syria, China calls for resolving the conflict in a way acceptable to all parties, and has sided with Russia three times to veto Western-proposed UN Security Council resolutions that would increase pressure on President Bashar al-Assad.

Ban, a former South Korean foreign minister, is also scheduled to hold talks with Chinese Premier Li Keqiang on Thursday.

His visit to Beijing was interrupted by news of an attack by Al-Qaeda-linked Shebab insurgents on a UN compound in Mogadishu on Wednesday that killed nine people in the most serious attack on the UN in the troubled country in recent years.

Nesirky described Ban as being "shocked" by news of the attack and that he was "being updated regularly" on the situation.