Four men have pleaded guilty to producing drugs on a large scale in the Gold Coast hinterland.
Two of the men were found with over one kilogram of pure methylamphetamine when police raided a Beech mont house in 2010.
At the time police said the drugs had a street value of up to $3 million.
Dino Spizzirri, Jason Hinton, Stephen Creighton and Kevin O'Hara pleaded guilty in the Brisbane Supreme Court on Monday to producing drugs and possessing items used in the commission of a crime.
Creighton, 54, also pleaded guilty to drug trafficking and possession.
The court heard Spizzirri, 56, was the ringleader and Hinton, 34, was his right-hand man.
O'Hara, 31, sourced the chemicals and cooking implements and Creighton sold the drugs from the warehouse of his business.
Police tapped the men's phones and hid a camera in the warehouse during a covert surveillance operation in late 2009 and early 2010.
The surveillance paid off in May 2010 when police raided the Beech mont house and found Spizzirri and Hinton with the methylamphetamine in the final stages of production.
Crown prosecutor Sarah Frandsen called it a sophisticated operation which took some time to set up.
"This is clearly a commercial production on a large scale," she told the court.
The men are expected to be sentenced later on Monday.
Creighton's barrister Dennis Lynch said his client started selling speed to fund his own habit and had lost his business, his house and his wife.
Spizzirri's barrister Tony Kim mins said his client had health problems and would find prison tougher than an able-bodied person.Judge Alfred Daubney adjourned the sentencing until Thursday, saying there was a lot of material to consider.