It says something about their relationship that they have now met too many times to count.
Mr Key has been to China five times as Prime Minister since 2008, most recently last week.
If Mr Xi, 61, follows tradition, he will rule the largest country on earth for 10 years. But he is not a traditional leader. He is said to epitomise China: tall, strong, confident and assertive. He is not afraid to show his personality, or to have his wife, Peng Liyuan, become the first First Lady of China, western-style.
He has carved a reputation as the most powerful leader since the reforming Deng Xiaoping, and preferring his own judgment over the consensus style of the post-Mao old-guard. He is seen as a determined agent for reform domestically, and in regional and international roles.
But like post-revolutionary China, his rule is full of contradictions.
Domestically, Mr Xi has begun a popular campaign against corruption and excess in the party, the most senior among them Zhou Yongkang, a former head of state security. But there has also been a crackdown on social media and dissent.
Regionally Mr Xi has taken relationships close to breaking point over territorial disputes with Japan and other neighbours but is also looking for ways to show regional leadership such as through the Asian Infrastructure Investment Bank and the Free Trade Area of the Asia Pacific, promoted at the Apec summit.
The contradictions abound: as the son of a hero of the Long March, Xi Zongxun, who was vice-Premier under Zhou Enlai, he lived in a compound for the elite in Beijing. But his father was denounced during the Cultural Revolution and sent to work in a tractor factory and Xi Jinping is reported as telling a magazine he lived for seven years in a cave home in Lianghjiahe where he endured fleas, hard labour and loneliness.
An open letter to New Zealand
For a Better Future of the China-New Zealand Relations
Tonight, I will begin my first visit to New Zealand as the President of the People's Republic of China, bringing with me the friendly sentiments of the Chinese people to the people of New Zealand and an ardent wish to grow the China-New Zealand friendly relations.
New Zealand is a shining pearl on the Pacific Ocean, a country blessed with a hardworking, courageous and warm-hearted people, a dream place of idyllic beauty, and a land of abundant resources that are much favoured in the global market. The upcoming visit will be the third time for me to set foot on this beautiful country, and I am very much looking forward to the trip.
Every time I come across the subject of China-New Zealand relations, two touching stories will come to my mind. In May 2008, a massive earthquake struck Wenchuan County, Sichuan Province of China. A group of lovely children in Christchurch, South Island of New Zealand decided to do something for those affected in China to overcome difficulties. In spite of the cold wind of the Southern Hemisphere which was in its winter, the children went to the street and played the violin to raise money for the quake victims. In February 2011, Christchurch was also hit by an earthquake. On hearing this unfortunate news, the international rescue team of China responded swiftly and joined rescue operations immediately, contributing their share to the search and rescue of those trapped. As shown in both stories, although China and New Zealand are separated by the vast ocean, there is strong empathy between our two peoples in times of need. This is an epitome and a vivid example of friendship between China and New Zealand.
Since the establishment of diplomatic ties in 1972, the China-New Zealand relations have made historic strides forward, and practical exchanges and co-operation in various fields have reached unprecedented breadth and depth. The two countries have set many records in China's relations with developed countries. For example, China is now the largest trading partner and source of international students for New Zealand. In particular, New Zealand is the first developed country to have signed and implemented a free trade agreement with China. From more quality and inexpensive goods and services to more jobs, from more convenient people-to-people exchanges to better study opportunities, more and more visible and tangible benefits are made available to our two countries and peoples as a result of our friendly co-operation.
The journey of China-New Zealand relations proves that mutual respect and equality underpin the sustained, sound and steady growth of the bilateral ties, complementarity and mutual benefit give strong boost to the rapid expansion of practical co-operation, and the pioneering spirit and the readiness to seek common ground while shelving differences provide an inexhaustible source of strength to keep the bilateral relationship at the forefront of China's relations with developed countries. The China-New Zealand relations have gone beyond the bilateral scope and set a fine example for the pursuit of successful state-to-state relations.
In both China and New Zealand, strong winds of reform and development are sweeping across the country. The Chinese people are striving to fulfil the Chinese dream of great national renewal, comprehensively deepening the reform and opening-up programme, and advancing the rule of law across the board. New Zealand is making efforts to enhance its international competitiveness, step up infrastructure development, increase scientific and technological innovation input, and improve the economic structure. This has brought more converging interests between China and New Zealand. Aligning our development strategies effectively, we will have the rare opportunities and broad prospects for even stronger co-operation in all fields.
Under the new circumstances, friendship and co-operation between China and New Zealand have taken on a new mission. To better achieve development and prosperity in both countries, we need to join hands and build a better future of China-New Zealand relations.
Forge a new pattern of converging interests.The two countries need to advance practical co-operation in various fields and build a strong community of common interests. We should consolidate the basis of co-operation in agriculture, husbandry and other traditional sectors, and at the same time create new bright spots of co-operation. With China's strengths in infrastructure and manufacturing and New Zealand's advantages in agricultural science and technology, IT and clean energy, the two countries have much to offer to each other and may draw upon each other's strong points. The two sides should be committed to win-win co-operation, keep the markets open and create a more friendly and level playing field for our companies to access each other's market, make investment and grow businesses.
Open new horizons for cultural and people-to-people exchanges.Governments of the two countries should create conditions to facilitate more people-to-people exchanges. New Zealand is a popular filming location for more and more Chinese TV and film producers. The natural beauty of its landscape and the sincerity and kindness of its people have left the Chinese audience with very fond impressions. I am sure this will attract more Chinese tourists to New Zealand. The two countries are having talks on a television co-production agreement. This agreement, once signed, will inject new vitality into the cultural and people-to-people exchanges between China and New Zealand.
Raise co-ordination in multilateral arenas to a new level.Both China and New Zealand are participants of and contributors to the current international system, and as such, we should enhance co-operation. I wish to congratulate New Zealand on its election as a non-permanent member of the UN Security Council for 2015-2016. This demonstrates the importance the international community places on New Zealand's international standing and influence. China stands ready to increase co-operation with New Zealand in the United Nations, Apec, the Pacific Islands Forum and other regional and international mechanisms to advance our common interests and work with the international community to uphold regional and global peace and stability.
A famous Maori adage says, "Your livelihood is in your own hands". A new journey of co-operation for China and New Zealand is about to begin, and the future of China-New Zealand relationship is in our own hands. In the upcoming visit, I am looking forward to having discussions with the New Zealand Government and people from various sectors about ways to advance our co-operation and to joint chart the course for the growth of our bilateral ties. China is ready to move forward hand in hand with New Zealand as good partners for win-win co-operation and good friends sticking together through thick and thin, and work together for an even better future of China-New Zealand relations.
President Xi Jinping
• Son of Communist Party luminary, Xi Zhongxun
• Joined Communist Party in 1974
• Married to Madam Peng Liyuan, formerly a famous singer with the Peoples Liberation Army.
• One daughter, studying in the United States
• Studied chemical engineering at Tsinghua University, Beijing
• Worked his way up the party hierarchy
Career: Became Shanghai Party Secretary in 2007; Vice-President 2008; Vice-chairman of the Central Military Commission 2010; General Secretary of Communist Party 2012; President of China and chairman of Central Military Commission 2013.