Auckland, New Zealand's largest city, hopes to encourage even greater cooperation between China and the United States, Auckland Mayor Len Brown told Xinhua on Monday.

Auckland was well-placed to bring the three countries together as the "triangle of the Pacific," Brown said in an exclusive interview at the Tripartite Economic Summit of leaders from Guangzhou, Auckland and Los Angeles.

"We put ourselves there willingly with the expectation that we know that there are challenges that China and America face and in how they communicate and engage with each other," said Brown.

"We have outstanding social, political and cultural relationships with both those nations and they see us as safe. So the Tripartite (relationship) is a classic example of New Zealand, in this instance, Auckland, acting as a go-between, a greaser of the wheels of political, social and economic engagement between China and America," he said.

"Ultimately because we play that role, we are the beneficiaries too. It's a win-win for everyone, a win-win for global peace and prosperity and a win-win for little old New Zealand, right at the bottom of the world, being able to sit between these great powers."

Brown said the relationship between Auckland, New Zealand's largest city and home to a third of the population, and Guangzhou had seen "quantum growth" in recent years.

Guangzhou was his closest working relationship in terms of Auckland's sister cities.

"This relationship goes back to the 1850s, 1860s city-to-city. A lot of the original Chinese migrants out of China coming to New Zealand came from Guangzhou, so it's a very old relationship, but one that is burgeoning quite significantly," said Brown.

Direct flights by China Southern Airlines between the two cities had seen visitor numbers grow by more than 30 percent and relations would only get stronger.

"The engagement, with the free trade agreement between New Zealand and China at its base and the very strong political relationship, is very respectful at the national level," he said.

"At the city level, we've got two other sister cities in China, Qingdao and Ningbo, and the relationships are as strong with those cities. At the base of them is a good trusting relationship at the political level and behind that you have a powerhouse economic engagement and I can see nothing but blue sky for that."