North Korean leader Kim Jong-un has visited the Chinese city of Dalian to meet President Xi Jinping, China's official Xinhua news agency has reported.

Key points: Mr Kim said he hoped for "phased" measures towards denuclearisation

Mr Kim said he hoped for "phased" measures towards denuclearisation Mr Xi described the visit as a "special trip", according to state media

Mr Xi described the visit as a "special trip", according to state media The US Secretary of State is en route to North Korea for talks

The two discussed bilateral issues, with Mr Xi telling Mr Kim of his support of talks between North Korea and the United States, Xinhua said.

China has been keen to show it has an indispensable role in seeking a lasting solution to tension over North Korea's pursuit of nuclear weapons, concerned that its interests may be ignored, especially as North Korea and the United States establish contacts.

During the visit, announced only after it was over, Mr Kim told Mr Xi he hoped relevant parties would take "phased" and "synchronised" measures to realise denuclearisation and lasting peace on the Korean peninsula.

"As long as relevant parties eliminate the hostile policy and security threats against North Korea, North Korea does not need to have nuclear weapons, and denuclearisation is achievable," Mr Kim said.

"We hope to build mutual trust through dialogue between North Korea and the United States … and ultimately realise denuclearisation and lasting peace on the peninsula."

Kim Jong-un and Xi Jinping spoke about denuclearisation during a meeting in Dalian. ( AP: Ju Peng/Xinhua )

Mr Xi said Mr Kim's trip to China for a second time this year show's how important strong relations between the two countries are, particularly given the current situation on the Korean Peninsula.

"Kim Jong-un made a special trip to China to meet with me again within 40 more days," Mr Xi said.

"This shows that Mr Kim and the DPRK Central Committee attach great importance to the relations between China and North Korea.

"I am happy for the positive progression of both the China-DPRK relations and the situation in the Korean Peninsula since the first time when I met with Chairman Kim."

Mr Kim visited China in March for the first time since taking power six years ago, a trip that was not publicly confirmed by the two sides until after he had returned to North Korea by armoured train.

Chinese media said Mr Xi and Mr Kim met for a second time on Monday and Tuesday in China.

US President Donald Trump and Mr Xi discussed developments on the Korean peninsula and Mr Kim's visit to China during a phone call on Tuesday morning, the White House said.

Mr Trump and Mr Xi agreed on the importance of maintaining sanctions on Pyongyang until it permanently dismantles its nuclear and missile programs.

The visit comes ahead of a planned summit meeting between the North Korean leader and Mr Trump.

US Secretary of State Mike Pompeo is currently on his way to North Korea to finalise the details of that summit.

Mr Trump will also meet South Korean President Moon Jae-in at the White House later this month.

ABC/wires