Australia's system of organic certification will come under intense scrutiny when two neighbouring farmers do battle in the Western Australian Supreme Court in a test case on genetically modified crop contamination.

Organic farmer Steve Marsh, from Kojonup in the state's Great Southern region, is suing his neighbour Michael Baxter for alleged negligence and nuisance.

Mr Marsh claims genetically modified (GM) canola seed blew onto his farm in 2010, causing him to lose his organic status.

He says he is prepared to risk his 480-hectare property to defend his right to farm without interference.

"It's totally about freedom of choice," Mr Marsh said.

"The GM proponents, they've argued for their rights to grow and use GM, this tool in the toolbox.

"All I'm asking is for the same right to be able to produce a GM-free product which we've traditionally done for years.

"I think that's very important because as farmers we should have the right to run our business and produce products that we choose to."

http://www.abc.net.au/news/2012-07-06/organic-certification-row-to-head-to-wa-court/4114336?WT.svl=news4