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Genetically modified pastures are coming to New Zealand, experts say.

Speakers at a biotechnology conference in Auckland last week said crop technology was developing fast and the public mood towards genetic modification had changed as the world's population grew and food prices rose.

But GMFree New Zealand says the introduction of GM crops could put our international reputation at risk.

Genetically modified pastures are not banned in New Zealand, but there has yet to be a crop approved for release here.

Colin Harvey, director at animal health development company Ancare Scientific, who is also a past president of NZ Agritech, chaired a panel discussion on the introduction of GM crops.

"It's not if, it's when," he said.

Research organisations were gearing up to make applications to release GM crops into the New Zealand market.

" I think the public is even prepared to accept it," Harvey said.

The debate surrounding genetic modification has been emotive.

In January, genetically modified trees were cut down after those responsible had dug their way under a perimeter fence in an apparent protest at Crown forestry research institute Scion.

But Harvey expects that when an application for release of a pastoral plant is made the debate will be more informed.

Farm-based biologicals company South Pacific Sera co-founder William Rolleston said the public mood toward genetically modified crops had changed.

In 2002, he needed a bodyguard to attend a biotechnology conference.

"Tensions we're running extremely high," Rolleston said.

"That's not happening now and that probably says something about the debate."

There was a need to develop new crops as the global population increased and food prices rose.

"It's not just a global benefit," Rolleston said. "It's a global imperative."

The world population was growing and by 2050 was expected to be 40 per cent larger than today, he said.

"That means we're going to have more people and less land on which to grow produce."

In the early 1960s people were told the world would run out of food and people would starve but a green revolution with the use of pesticides, herbicides, fertilisers and hybrids boosted productivity, he said.

"For genetic modification we want to reduce our environmental footprint, we want to increase productivity and we want economic sustainability," he said.

"I guess I could be giving a lecture on organics and say we had exactly the same goals."

A Eurobarometer survey in Europe showed that if consumers saw an environmental or a personal benefit from a genetically modified product then 54 per cent would buy it, he said.

"So the tide is definitely turning from that point of view."

But GE-Free New Zealand spokesman Jon Carapiet said as well as the safety issue of GM crops there was concern about how it would affect New Zealand's image.

"There's the actual safety issue of these pastures and the impact on the animals, but at the end of the day there's also an issue of brand New Zealand," Carapiet said.

"The international reputation which we trade on is a sort of clean, green but also a natural kind of component."

There was a need for caution around both scientific and brand image aspects of research and applications.

One of the areas in which progress is being made in New Zealand is cisgenics - modification that uses only the genes from the species itself.

Zac Hanley of Pastoral Genomics, a non-profit research consortium working on cisgenics, said some people had a twitchy response to genetic modification technology.

"I think that it's possible to argue that a cisgenics type approach will allow people to be less ick-responsive."

A cisgenics plant could already exist naturally, he said.

"It's a big old world, 3.5 billion hectares of pasture out there.

"Any single thing that we're going to produce from our cisgenics strategy is probably already out there in the field.

"We're just making it because it's too hard to find it."

Hanley said a marketable product could come out of the wider GM sector by 2016.