THE historic seizure of 15 tonnes of pure methamphetamine in western Mexico - equal to half of all meth seizures worldwide in 2009 - feeds growing speculation that the country could become a world platform for meth production, not just a supplier to the United States.

The sheer size of the bust, announced late Wednesday in Jalisco state, suggests the involvement of the powerful Sinaloa cartel, a big international trafficker of cocaine and marijuana that has moved into meth production on an industrial scale.



Army officials did not say what drug gangs could have been behind the dozens of blue barrels filled with powdered meth.



Army General Gilberto Hernandez Andreu said the meth was ready for packaging. There was no information on where the drugs were headed.



Jalisco has long been considered the hub of the Sinaloa cartel's meth production and trafficking. Meanwhile, meth use is growing in the US, already the world's biggest market for illicit drugs.



The haul could have supplied 13 million doses worth more than $US4 billion ($3.72 billion) on US streets.



The Sinaloa cartel, headed by Joaquin "El Chapo" Guzman, is equipped to produce and distribute drugs "for the global village," said Antonio Mazzitelli, the regional representative of the United Nations Office on Drugs and Crime.



"Such large-scale production could suggest an expansion ... into Latin American and Asian markets," Mazzitelli said.



But he noted: "It may be a product that hasn't been able to be sold, and like any business, when the market is depressed, stockpiles build up."



A senior US law enforcement official in Mexico said the operation raided in Jalisco was "probably Sinaloa".



The official, who could not be quoted by name for security reasons, said Sinaloa may be trying "to reduce its reliance on Colombian cocaine by flooding the market with meth".



Reporters were shown barrels of white and yellow powder that filled three rooms on a small ranch outside Guadalajara, Mexico's second-largest city.



The area around the house, which included an empty swimming pool, was littered with metal canisters and cauldrons used in the production process. Although the equipment appeared makeshift and was partially dismantled, it had apparently been used intensively.



There were no people found on the ranch or arrests made, although it appeared 12 to 15 people had worked there.



The seizure of such a large quantity of meth is expected to have a big impact on the US meth market.



"This could potentially put a huge dent in the supply chain in the US," said US Drug Enforcement Administration spokesman Rusty Payne. "When we're taking this much out of the supply chain, it's a huge deal."



But that may not ultimately mean less meth in the US. Law enforcement officials in California's Central Valley, a methamphetamine distribution hub, say a cutoff in the Mexican supply could mean domestic super labs will increase production.