North Korean leader Kim Jong Un welcomes Chinese President Xi Jinping. (Reuters)

North Korean leader Kim Jong Un and Chinese President Xi Jinping have agreed that strengthening bilateral ties, at a time of "serious and complicated" international affairs, was good for regional peace, North Korean state media said on Friday.

Xi arrived in Pyongyang on Thursday for a two-day visit, the first by a Chinese leader in 14 years, and received a lavish welcome that included a performance of the song "I Love Thee, China" and thousands of people holding up placards that formed a picture of Xi's face and the Chinese flag.

China is the North's only major ally and Xi's visit is aimed at bolstering Pyongyang against pressure from U.N. sanctions over its nuclear and missile programmes and a breakdown in denuclearisation talks with the United States.

The visit also comes a week before Xi and US President Donald Trump meet at the G20 summit in Osaka amid an ongoing trade dispute.

North Korean leader Kim Jong Un and Chinese President Xi Jinping attend a banquet in Pyongyang. (Reuters)

Video footage and photos released by North Korean state media showed Kim and Xi with wide smiles at Pyongyang airport. They drove through the streets of the capital in an open top limousine, and later attended a "Mass Games" propaganda show.

The show - titled "Invincible Socialism" - was specially prepared for Xi's goodwill visit and included songs such as "No New China without Communist Party" and "I Love Thee, China", the KCNA news agency said.

One sign in Chinese read: "Happy to see you Grandpa Xi".

A photo released by KCNA showed thousands of people holding placards to form a giant picture of Xi's face and the Chinese flag at the mass gymnastics and arts performance.

Other KCNA photos showed Xi and Kim smiling and laughing at the airport, on the red carpet, gazing at cheering children and sitting with their wives.

The ruling party's main newspaper, Rodong Sinmun, ran a special expanded edition on Friday, with eight of 10 pages devoted to photos and text about Xi's visit.

DECISIVE RELATIONSHIP

Kim said Xi's visit, which may see China offer fresh support for North Korea's floundering, sanctions-bound economy, was "decisive" to show their unchanging friendship to the world, KCNA said.

Nevertheless, relations have been strained at times, particularly over North Korea's nuclear programme.

Xi said Beijing and Pyongyang agreed that a political settlement of the Korean peninsula's nuclear issue has been "an inevitable trend," and that they need to continue to stick to peace talks, according to Xinhua, China's state news agency.

The two leaders agreed to promote close strategic communication and strengthen cooperation in all fields, KCNA said.

On Thursday, Xi praised Pyongyang's efforts towards denuclearisation and said the world hopes North Korea and the United States can talk to each other and for those talks to be successful.

Since a failed summit between Trump and Kim in Hanoi earlier this year, Pyongyang has conducted some weapons tests and warned of "truly undesired consequences" if the United States is not more flexible.

At a dinner banquet on Thursday, Xi said China firmly supported Kim seeking a political solution to the Korean Peninsula issue and the establishment of a great environment for self-development via a "new strategic line", according to KCNA.