The man who New Zealand kiwifruit marketer Zespri is suing for infringement of its intellectual property rights has been named by the country's High Court as Haoyu Gao, website Newsroom reported.

Zespri is reportedly seeking damages of up to NZ$30 million for allegedly smuggling its proprietary G3 and G9 kiwifruit varieties into China.

Gao, his wife Xia Xue and their company Smiling Face Ltd are at the center of the lawsuit alleging plant material taken from New Zealand has been used for at least four orchards covering 167 hectares of land in China.

China is one of the world's biggest markets for kiwifruit and Zespri claims to have had big plans to export the gold kiwifruit there.

Zespri now also claims that Gao may have also smuggled the plants into Australia, Newsroom reported.

The High Court has heard of an extensive inquiry by Zespri in China involving private eyes and also New Zealand border protection agencies searching Gao as he left to and returned from China with grafting tools, a police investigation that did not lead to a criminal prosecution but delivered phone and social media records to Zespri, and samples of fruit and leaves being secured and DNA tested from the Chinese orchards.

The company reportedly started pursuing Gao after a WeChat group discussion about gold kiwifruit plants featured a photo of Gao's New Zealand grower number, #914.

It alleges he signed a fake authorization contract with China-based grower Changqing Shu purporting to give Shu the rights to not only sell the gold kiwifruit varieties in "the entirety of China" but also to sell the plant material across the country, the story reported.

Zespri's global production manager Shane Max said in evidence this week that documents, which Zespri obtained under the Official Information Act after the police investigation, showed Gao also conspired to export its G3 and G9 plant material to a grower in Victoria, Australia.

The trial is ongoing and expected to last all this week, according to Newsroom.