"This relationship has been building for 10 years during which representatives from [the Hainan province] have visited Whangarei," Ms Mai said.
"Discussions between our cities will initially focus on international education via NorthTec which has had a bilateral international education relationship with China for many years.
"The coming years will bring regular contact between the leaders and relevant departments of the two cities to ensure communication, exchange and consultation on issues that could benefit both cities.
"Encouraging and stimulating business activity and investment is a key objective."
Haikou, with a population of just over two million, is the capital and biggest city of Hainan province.