''Bloody idiot,'' grumbles Kavasilas. ''They're everywhere around here and you reach a point where you just lose patience …''

It's not that Kavasilas doesn't like pot. Quite the contrary: Until recently, he owned this cafe, the Oasis, and was a central figure in the ever-changing hippie culture that made Nimbin one of the world's best-known ''cannabis-friendly'' destinations. He took part in (legal) research into growing high-strength cannabis, wrote a book about its medical uses, ran a mail-order service providing the drug to medical users and was busted, in 2001, for possession when he and other Nimbin cafe owners conducted (illegal) ''trials'' for the regulated sale of cannabis.

But over time Sydney-born Kavasilas has grown weary of Nimbin's rag-tag army of blow-ins, often just out of prison, who take advantage of the tolerant mood to sell hard drugs such as heroin on the streets. ''There's been violence and real turf wars between some dealers,'' he says. ''And normal people, who come here just to get a bit of pot for their own use, were worried about getting embroiled in a violent incident, or being stood over.''

So Kavasilas began focusing his knowledge of cannabis on industrial hemp - a variety with low levels of the psychoactive element tetrahydrocannabinol, or THC - grown not as a drug but to make clothing, textiles and building materials, and as a nutritional food source using the seeds and oil. ''A few years ago,'' he says, ''I decided to go full-time into growing hemp for food.''

To improve his dealings with politicians and other influential types, Kavasilas shed his beloved dreadlocks, sold the Oasis and - with a state government permit - became one of a handful of farmers legally growing industrial hemp in NSW.

At 46, the father of two still smokes the illegal variety. As is the custom in the Rainbow Country's little slice of Amsterdam, he fires up openly at the cafe table, and soon warms to his favourite theme. ''As a businessman and entrepreneur,'' he says, ''I see hemp as the perfect product. It is the most nutritional grain for human consumption - better than fish oil for pregnant women - with a high content of omega 3, 6 and 9, plus all the known amino acids and a very good array of vitamins, minerals and trace elements, but delivered in a more digestible form than tablets.''

Sounds good, but there is one not-so-small problem. While it's legal (with a permit) to grow low-THC hemp for consumption in Australia, it's illegal to consume it here in any form. Australia is the only country in the world with such a prohibition, even though the hemp involved has no effect as a drug.

Australia's official argument against hemp food is that it will undermine the national cannabis strategy (implemented by the Howard government in 2006) by sending mixed messages about the safety and use of cannabis, and that police wouldn't be able to tell the difference between the low- and high-THC seed varieties.

Kavasilas, who has been lobbying hard against the ban, reckons it's as irrational as the original prohibition against marijuana that was rushed through the US Congress in 1937 - seemingly to benefit industrialists producing cotton and synthetic fibres - and later adopted by most of the Western world. (Congressional hearings leading to the ban were told by the Federal Bureau of Narcotics that marijuana use caused ''insanity, criminality and death''. The same hearings were told by a Dr William C. Woodward, on behalf of the American Medical Association, that ''the [association] knows of no evidence that marijuana is a dangerous drug''.)

Kavasilas says fears of hemp food undermining the cannabis strategy are silly because the strategy hasn't worked. ''Australia has 2 million known cannabis smokers and the highest use per capita in the world. Through various state laws, we've decriminalised use and personal possession. Police and the judiciary can't be said to be administering cannabis laws in the spirit in which they were written because that spirit was to wipe cannabis off the face of the earth.''

Although he believes the regulated sale of recreational marijuana should be legalised, Kavasilas adds that, like alcohol, it ''isn't for everyone'', and shouldn't be sold to those under 18 - ''Let your mind grow before you make it expand'' - or used by anyone with indications of psychosis or schizophrenia.

At his home in a peaceful valley near Nimbin, Kavasilas has an array of hemp foods - oils, milks, flours, cereals, snack bars - to show visitors involved in the continuing legality debate. His most recent callers were two representatives of Food Standards Australia New Zealand, which is supportive of the potential new industry.

The Food Standards reps were boning up on growing and processing aspects of hemp food in readiness for a meeting in December with the Ministerial Council on Drug Strategy, whose approval is needed to lift the prohibition. After feeding them hemp cake, Kavasilas took his visitors to a processing facility where he stores the seed from the 12 hectares or so of hemp he has already grown (on two northern NSW properties where space was leased amid more conventional crops), but can't sell until the food wrangle is settled.

Interestingly, given the prohibition's background, Americans are now legally devouring about $30 million worth of hemp foods a year. And while Australians can grow industrial hemp but not eat it, Americans can eat it but not grow it. So the lot has to be imported, mostly from Canada. (China and India remain by far the biggest worldwide exporters of industrial hemp seed.)

Another quirk of the hemp wars, wherever they occur, is that organised criminals behind large illegal dope crops don't want legal hemp being farmed near their own.

''We've got an illicit cannabis industry worth about $6 billion a year,'' Kavasilas says. ''That's twice the size of our wine industry. And if low-THC hemp fields started springing up all over the place, their pollen can reach the high-THC crops and spoil them, turning them into seedy, low-THC stuff that people won't buy.''

Not long ago, Kavasilas himself was warned off by an illegal grower. ''I was told in no uncertain terms never to grow industrial hemp in a certain area. This wasn't in Nimbin, where [despite annual police helicopter raids] most growing involves just a few plants for personal use.''

Kavasilas sees ''unpleasant'' similarities between the forceful opposition of organised crime to industrial hemp and the arguments being put by some of its other opponents. ''Whatever organised crime wants to say [against industrial hemp] seems inevitably to come through the mouths of various [political figures]. I hope they don't realise that criminals could be using them, because that would make it a lot worse.''

My last call in Nimbin is at a ramshackle old building in the main street that has traded for decades as the Hemp Embassy. Owned by a one-time Victorian stockbroker, Michael Balderstone, it sells dope paraphernalia and a vast range of publications about the history and virtues of pot.

At the rear of this sprawling edifice lives the Embassy's vice-president, Alan ''Salty'' Salt, who arrived in Nimbin in 1974 - a year after the famous Aquarius Festival launched the town's counter-culture movement. He seems the right person to ask an obvious question: given that dope is illegal in NSW, why don't authorities crack down on the town's overt displays of selling and smoking?

''They do!'' Salt says. ''The police do undercover operations here quite often. But it's quite futile. For every two people they bust and take away, two more turn up … in that sense it's the same as, say, Darlinghurst in Sydney. There are simply more [marijuana users] there, and everywhere else for that matter, than they can ever deal with.''

My scoop from the Embassy is that vice-president Salt is no longer one of them. Diagnosed with emphysema, he gave up smoking pot a year ago. ''I don't really miss it,'' he reports. ''When I was younger I always wanted to be taking things and partying on. At 59, I don't feel like that any more. In fact, I actually feel good that I'm not smoking.''