WELLINGTON - Slowing growth in the global economy is holding back New Zealand's economy, but China is still providing major opportunities for trade, Finance Minister Bill English said on Thursday.

Low inflation globally was dragging down commodity prices, but had the benefit of lowering New Zealand's exchange rate too, English told a gathering of New Zealand and Australian business leaders in Wellington.

Dairy prices fell 65 percent from a high in February 2014 to a low in August this year, which was having an impact on other sectors of the economy, English said in the published speech.

"The fall in dairy prices has contributed to a significant depreciation in the New Zealand dollar, which is down more than 25 percent against the US dollar since mid-2014," he said.

Unfortunately the global economy appeared to have hit another weak patch, which meant New Zealand's economic growth could drop from about 3 percent forecast last year to a little below 2 percent for the first half of this year.

"I returned from IMF (International Monetary Fund) and World Bank meetings in Peru on Monday. These reaffirmed that slowing growth in China and other emerging economies like Brazil is a concern for the world economic outlook," said English.

"However, the composition of China's growth is important. Its investment-driven growth cycle is waning, but this is being replaced by consumption and services driven growth from a rapidly expanding middle-class," he said.

"This is a big opportunity for New Zealand, given our major exports are in softer commodities like dairy, beef and lamb, and also for our services companies, whether they be in tourism, technology or business services."

Speaking the day after New Zealand's center-right government reported its first operating surplus since coming to power in 2008 for the fiscal year to the end of June, English said slowing global growth highlighted the need for ongoing fiscal restraint.

"Reaching surplus was a significant milestone, and one the public service can be proud of. But the job is far from done, we now need to focus on getting debt down," English said.

"A weaker global economy and lower inflation outlook means (government) revenue is likely to grow slower than previously expected."