Former Prime Minister John Key is taking Zespri's kiwifruit fight straight to top Chinese politicians.

Zespri filed a civil case in China's Intellectual Property Court in August, against parties it claims are growing unlicensed golden kiwifruit.

Key has since spoken with China's foreign affairs minister Wang Yi on a business trip to Beijing to ensure Kiwi farmers have confidence their intellectual property is protected.

The Country's Jamie Mackay says China's unlicensed growth is a threat to Zespri's sales, as 25 percent of their total sales come from the region.

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