South Korean President Moon Jae-In hopes to “normalise” ties with giant neighbour China on his first state visit to the country this week, his office said on Monday, after Beijing was infuriated by a US missile system deployment.

Seoul and Washington decided to install the powerful US THAAD (Terminal High Altitude Area Defense) system in the South earlier this year to guard against threats from the nuclear-armed North.

Beijing saw it as a threat to its own security and reacted furiously, slapping a string of measures against South Korean businesses and banning group tours to the South, in moves seen as economic retaliation.

China is the South's top trading partner and the diplomatic row took a major toll on many South Korean firms, most notably retail giant Lotte Group, which provided the land to host the powerful US missile system.

Angry boycott campaigns and regulatory crackdowns by Chinese authorities decimated its business in the world's second-largest economy, and it was forced to put its supermarket unit in China up for sale.

But last month the two countries issued identically-worded statements on their mutual desire to improve relations.

It did not state any specifics, but Beijing has demanded that Seoul formally promise not to deploy any more THAAD launchers and not to join any regional US missile defence system.

Nam Gwan-Pyo, a deputy director of the presidential national security office, did not give reporters details of any concrete steps that could be expected from Moon's four-day trip ─ his first to China since taking power in May.

But he said it would be a turning point in relations towards a “more mature” relationship, he said, “by recovering bilateral trust and strengthening friendship between the leaders of the two nations”.

Ties recently showed some ─ albeit limited ─ signs of thaw as China's state tourism board approved last month Seoul-bound group tours from some parts of China.

Moon heads to Beijing on Wednesday and will hold a summit with Chinese President Xi Jinping the following day to discuss issues including how to curb the North's nuclear weapons drive, Nam added.

China ─ the North's sole diplomatic ally and economic lifeline ─ has stepped up sanctions on the North amid pressure from the US and the international community to play a bigger role in taming its regime.

Beijing has backed recent UN sanctions imposed on the North over its nuclear and missile tests, including a ban on coal imports, although it repeatedly pushed for talks to defuse the tensions.

It has urged a “double freeze” on both North Korean weapons tests and joint military exercises by Seoul and Washington ─ an idea consistently rejected by the US and South Korea.