A landmark court case to decide on a farmer's right to produce genetically modified crops begins in the Western Australian Supreme Court today.

An organic farmer in Kojonup, Western Australia, is suing his neighbour for loss of income and damages after his property was allegedly contaminated with genetically modified (GM) canola.

Kojonup, 260 kilometres south-east of Perth, is home to about 2,000 people, mostly multi-generational farmers involved in cropping and sheep production.

Steve Marsh is claiming financial compensation after losing organic certification for about 70 per cent of his farm. He alleges his property was contaminated by GM canola material from Michael Baxter's neighbouring property in November 2010.

At the time, Mr Marsh's property was certified organic by the National Association for Sustainable Agriculture Australia (NASAA), which has a zero tolerance for GM material.

Mr Marsh argues that swathed GM canola blew 1.5 kilometres inside the boundary fence of his Eagles Rest property.

He has gained strong support from interest groups like the Safe Food Foundation.

"We are concerned, depending on which way the result goes, that there is going to be a need for legislation," said foundation director Scott Kinnear.

"Really, what is about to happen is Steve Marsh's right to grow GM-free food will be reinforced or it will be taken away from him, and that equals our right, or the public's right, to eat GM-free food or perhaps not GM-free food into the future.

"We have to fight this as hard as we can. This is a pivotal time globally for GM, this common law case.

"It's a very difficult conundrum that's got to be solved."

Pastoralists and Graziers say a legal precedent will be set

The Western Australian Pastoralists and Graziers Association was quick to throw its support behind Mr Baxter, creating a 'fighting fund' to collect donations for his legal costs.

Chair of PGA's western grain growers John Snooke is frustrated by the lack of public support for choice in agriculture and the advantages of new technologies.

"When you look at the facts, Michael Baxter has done nothing wrong other than grow a legal crop.

"When you push the alarmism aside, the case is very clear, that Steve Marsh is trying to impose unnecessary conditions on his neighbour and trying to stop him growing GM canola.

"So we feel we are on very principled and solid ground. A legal precedent will be set."

A farming community in legal limbo

Since the first GM was commercially grown in WA in 2010, the Kojonup farming community has been gripped by an emotional debate around growing GM crops in their district.

Genetically modified crop contamination will come under intense scrutiny when two neighbouring Kojonup farmers do battle in the Western Australian Supreme Court ( Olivia Garnett )

"I think it might've put us on the map in a bad way," said Kojonup farmer Kate Mason.

Steve Marsh and Michael Baxter grew up on neighbouring farms and as boys caught the school bus into town together.

The families have been torn apart by this bitter court battle, which is being watched closely around the world.

It's something that's talked about a lot in the waiting room of the local Kojonup GP, Dr Anthony King.

"Most people would wish this thing had never gone to court," Dr King said.

"I think the concern of the community is that it causes division and a breakdown of community spirit, so we're disappointed about that."

Roundup Ready (GM) Canola was developed by biotechnology company Monsanto and is tolerant to glyphosate, the active ingredient in a commonly known herbicide.

Monsanto wasn't prepared to comment on whether it is financially supporting Michael Baxter during the legal battle.

Despite negative press around this case, the rate of GM canola plantings has increased across the country.

WA growers purchased a record 416 tonnes of Roundup Ready canola seed for the 2013 season, a 38 per cent increase over the previous year.

And some, like Rob Edgerton-Warburton of Kojonup, strongly argue its merits.

"The yields are outstanding and the weed control is also outstanding, so that's given us a lot of confidence.

"The important part is the benefit it brings to the rotation and being able to keep canola in the rotation for longer."

Being an organic producer in a district dominated by conventional growers has its challenges, but it's something organic oat and sheep farmer Kate Mason takes in her stride.

"Any business is all about relationships and, being an organic grower surrounded by conventional growers, it's about the relationships that you have with other businesses and we have really good relationships with all of our neighbours, so it's quite easy really," she said.

"It's our business and livelihood so we've got to make sure that it works and we do.

"It's not up to us to tell you what you should believe in and how you should farm. We're obviously farming how we want to and they can do what they want to as well."

Judy farms less than 10 kilometres from Mr Baxter and Mr Marsh in Kojonup and works at a local cafe.

She says having two farmers at loggerheads has caused uncomfortable relationships in the small town.

"There was a little community where they used to do sport. I don't believe they do that anymore because one might turn up and the other one doesn't want to be in the same area.

"And that's sad because that's sort of killing another family from another little sporting group. It needs to come to a head and be done with so everyone can get back to farming and doing what we all love best."

Three weeks are scheduled for the trial.