A DEADLY booby trap was used to protect a large drug crop found in an underground tank.
A metal door with 8000 volts of electricity running through it opened into the tank.
It could have killed anyone who didn't know how to shut the power off, police said.
They found the trap when they raided a shed on a property near Kyneton in Victoria last week.
Six officers found a wooden trapdoor behind a false wall.
Underneath it was the electrified trapdoor.
It opened on to a 50,000 litre water tank buried under a concrete slab.
Police seized 40kg of marijuana with an estimated street value of $160,000, watering systems and industrial-strength hydroponic lights.
Sixty-two plants were being grown in three sections of the tank beneath 22 of the lights.
Images show the marijuana plants, many mature, were flourishing in the secret tank.
Police allege that the electricity powering the elaborate set-up was stolen by an illegal hook-up into the mains electricity supply.
Boris Petovski, 46, of Reservoir, was arrested last Tuesday and charged with cultivating and trafficking a commercial quantity of a drug of dependence.
Mr Petovski is also charged with theft of electricity and two counts of setting up a man trap that could have caused death or injury.
He appeared in Broadmeadows Magistrates' Court last Friday on a $50,000 surety and was ordered to surrender his passport.
The court heard Mr Petovski told police the crop was for personal use.
Police swooped on the hidden operation after a month-long investigation.
Acting Sen-Sgt Michael Portoglou described the set-up as sophisticated.
"I've seen other hydroponic set-ups but I've never seen one underground," Sen-Sgt Portoglou said.
"It was very well set up, very sophisticated.
"How long it's been there it's hard to tell, but we know there are more out there."
Sen-Sgt Portoglou said the haul was the biggest in the area he could remember.
"We've had other hauls with 60-odd plants, but we haven't had this kind of weight," he said.
"We received information through a Macedon Ranges police hotline, based at Kyneton, and other sources."
In a separate case earlier this year, a court heard that a trapdoor hidden under a bathtub led to a 134kg crop grown in an underground room in Sunbury.
The discovery was made only after a sharp-eyed officer, who had recently renovated his home, noticed there was no silicone beading around the edge of the bathtub.
Source: Advertiser, The (Australia)