Australian scientists have helped discover what could be one of the only known causes of motor neurone disease.

The researchers were involved in discovering how a toxin in blue-green algae can contaminate food and cause problems in the central nervous system.

The cause of more than 90 per cent of motor neurone disease cases remains unknown.

Researchers are hoping the link found between motor neurone disease and blue-green algae could help treat the condition.

Lead author Dr Rachel Dunlop, from the University of Technology Sydney, says the findings will bring scientists a step closer to understanding motor neurone disease.

"We think [the cause is] a toxin that's found in blue green algae and can get into all kinds of food stuffs, into fish, into crustaceans, into seeds of trees," Dr Dunlop said.

"It can move through the food chain and bio-concentrate and when people are exposed to it, it seems to be able to trigger motor neurone disease in some people.

"It's fascinating. The algal toxin actually mimics an amino acid that humans use to make their own proteins, and if its in your body at the time, it can trick yourselves into thinking it's the one that you normally use.

"Then when it gets into your proteins it can prevent them from folding and functioning properly, and that can lead to toxicity."

Breakthrough might lead to treatment of fatal disease

Dr Dunlop says the research originated from her colleague Dr Paul Cox's observations in Guam, where the indigenous population has between 50-100 times more motor neurone disease than the general population.

"He discovered that they were eating fruit bats and when he went and looked at what the fruit bats were eating, he found they were eating the seeds of the cycad tree," she said.

"He scratched around in the roots of that tree and found that blue-green algae which also grows in the ground, not just in water, was actually growing as part of the roots of that tree."

The breakthrough might also help develop a treatment for the fatal condition, she says.

"The discovery that we found might help us to design a therapy to stop it getting in to people's proteins," she said.

"[It suggests that] if we could flush it out by giving people lots of the human version, then we can maybe stop this condition from occurring."

Dr Dunlop says clinical trials have started using the research to help find a treatment for the condition.

"They're in the very early stages so we can't make any predictions yet about whether or not they'll be successful," she said.

"But we're trying as hard as we can because it's such a dreadful disease."

The research is being published today in the journal PLOS ONE.