NEW Zealand's relationship with China is in "fantastic shape," Prime Minister John Key said yesterday in Shanghai as the two countries mark the positive benefits of a free trade agreement they signed.

Key mentioned China's ''promise'' to import US$10 trillion of goods annually in the next five years, as well as more than 400 million outbound tourists and US$500 billion worth of foreign investments.

"New Zealand is in fantastic shape when it comes to its relationship with China. Realistically, I'm not even sure it can get any better than this,'' Key said at a breakfast meeting organized by Kiwi Expats Abroad in China, part of his week-long tour of Guangzhou, Shanghai and Beijing.

His trip celebrates 40 years of diplomatic relations between the two nations and the fifth anniversary of the FTA, the first of its kind with an OECD country.

The FTA reduces tariffs on New Zealand exports to China, and is expected to save New Zealand NZ$115.5 million (US$98 million) annually.

Key said the FTA had impacted positively on China-New Zealand trade.

"In the five years since we signed the FTA ,we've done more business in the five years than we've done in every year combined prior to that," Key said. "We've sold more out of New Zealand to China in the eight hours you were in bed last night than in all of 1972."

He said New Zealand sold about NZ$3 billion (US$2.5 billion) worth of dairy products to China annually, which made up half of all dairy products imported into China, and 86 percent of the milk powder coming into China.