The 2010 World Expo opened in Shanghai, China, overnight with New Zealand's pavilion already proving a big hit.

Commissioner-General Phillip Gibson said that even before the opening, hundreds of people had come to touch a 12-metre-high steel and rubber pohutukawa tree which guarded the entrance to the New Zealand pavilion.

"We've had to build a barricade around it because it's been so popular," he told the Dominion Post.

A proud Shanghai threw open the gates of the 2010 World Expo, kicking off an event that underscores the Chinese financial hub's comeback as a major world city after decades of spartan industrialism following the 1949 communist revolution.

"Everything starts at the World Expo and all things come together at the Expo site," said Jia Qinglin, the Communist Party's No. 4 ranking leader.

The star-studded indoor festivities included action star Jackie Chan, Japanese singer Shinji Tanimura, concert pianist Lang Lang and opera star Andrea Bocelli, among 2,300 performers.

Like the 2008 Olympics, the expo is showcasing China's growing economic and geopolitical sway, both for the world and for its own public.

More than 70 million people are expected at the expo over the next six months, with 400,000 people a day expected to visit the New Zealand pavilion.

Mr Gibson said New Zealand had bagged a prime spot near the Chinese pavilion and in clear view of the millions who use one of Shanghai's main bridges.

A waka would be carved outside and an 1800kg pounamu boulder was already proving to be an attraction.

The main feature of New Zealand's $30 million pavilion - paid for by the Government and businesses - was a rooftop garden designed to reflect the diverse Kiwi landscape.

It included alpine mountain grasses, a bubbling mud pool, and a beautiful beach.

Beyond the scenery were business and political objectives.

"It's a great opportunity to showcase ourselves in a country that is increasingly critical to our economic wellbeing," Mr Gibson said.