In his speech at the event, Mr Xi described China's relationship with New Zealand as being "like a painting".
"It's a riot of colours and rich in content," he said. New elements could be added to it from both sides.
Mr Xi said there was a lot to be gained to advance the new strategic partnership at local lever and "step by step".
When he was deputy mayor of Xiamen, the city had a sister city relationship with Wellington - one of more than 1000 of Chinese cities with such relationships.
Among Mr Xi's delegation on his state visit are mayors from some of China's large cities including Guangzhou, with a population of 8.5 million and Wuhan with 8.3 million.
The agreement was signed by Local Government New Zealand president and Hastings Mayor Lawrence Yule and the president of the Chinese People's Association for Friendship with Foreign Counties, Li Xiaolin.
As well as Mr Yule, the New Zealand local government leaders present were: Auckland Mayor Len Brown, Wellington Mayor Celia Wade-Brown, Christchurch Mayor Lianne Dalziel, Dunedin Mayor Dave Cull, Tauranga Mayor Stuart Crosby and Hamilton Mayor Julie Hardaker.
The Chinese local government leaders were Chen Jianhua of Guangzhou, Xu Qin of Shenzhen, Liu Keqing of Xiamen, Tang Liangzhi of Wuhan, He Xiangdong of Lanzhou and Chen Gang of Guiyan.
Mr Yule said today's forum and the agreement provided a platform for regions, towns and cities across New Zealand to strengthen trade, economic, investment and cultural links with China.
"Currently New Zealand faces uneven economic growth with some regions growing faster and attracting population more than others.
"This agreement is a significant step to effectively building a level of sub-national engagement between the two countries that supports our regional development policy."
Mr Yule said that in the next 10 years, China's outbound investment was projected to exceed $1.25 trillion.
"We want to ensure that New Zealand, and most importantly our regions, attract some of this investment."
Chinese mayors had indicated they were most interested in New Zealand opportunities in agriculture, tourism, technology and education.
Several cities have hosted successful mayoral delegations to China in recent years that have resulted in business deals for companies in those regions.