The Australian pear industry would be the first to be wiped out if NZ apples are allowed into Australia, a leading industry spokesman says. The World Trade Organisation (WTO) launched an investigation of Australia's apple import rules as New Zealand seeks to export its fruit to its neighbour. It is the first WTO-brokered dispute between the countries which both have tough controls on agricultural imports to protect their island eco-systems.

New Zealand has said Australia's sanitary regulations on apples are not scientifically justified and violate world trade rules. But chairman of Apple and Pear Australia Darral Ashton says it is vital New Zealand apples are kept out as there is evidence of fireblight in the country. "Once it's established it's never eradicated and that's the case in 49 countries around the world and we don't want to be the 50th," Mr Ashton told AAP.

"It kills apple trees and a host of other plants and it can't be cured." The only way to control the spread of fireblight is to spray it with antibiotics, he said, but they are not available in Australian horticulture and are unlikely to be accepted. If fireblight was brought into Australia, Mr Ashton said pears would be the first affected.

"They're more susceptible than any apple so that would be the first port of call ... then the next variety of apples that are most susceptible are the Pink Lady apples ... and then the Gala variety", he said. "Between them they make up well over half of the plantings in Australia these days so an outbreak of fireblight on those would just devastate the Australian apple industry." Mr Ashton said it was not just the impact on trees that was a worry, but also the implications for growers and their families.

Mr Ashton said he was not surprised the WTO had decided to launch the investigation, but said it had reignited a fear within the industry's growers. Diplomats at the WTO's Dispute Settlement Body agreed to set up the investigative panel after New Zealand asked for a second time for it to be established. Last month Australia invoked its right to block New Zealand's first-time request for a panel, saying talks between the two countries were the best way to settle the dispute.

Even as the chairman of the peak industry group in Australia, Mr Ashton said he was unable to make any submissions to the inquiry. "It's now a government to government thing so all we can do now is talk to the people from government who are going to be there", he said. But he is confident the Australian government will do all it can to keep the New Zealand apples out of Australia. "I think the Australian government has stated publicly that it will be defending the protocols that they've recommended vigorously." Japan, the United States, Chile, the European Union and Taiwan, known as Chinese Taipei at the WTO, all signed on as third-party observers to the case.