Law enforcement agencies have chalked up two massive coups in the war on drugs, busting an industrial-scale NSW marijuana farm and also interdicting an Australia-bound shipment of Mexican meth.

Three people have been charged after a $15 million weed bust southwest of Sydney, after an overseas meth shipment was stopped from entering Australia.

Police raided a Douglas Park property on Friday afternoon as part of ongoing investigations into the cultivation of cannabis in rural areas across the Macarthur region.

Some 2817 cannabis plants, 14 greenhouses and manufacturing equipment were allegedly discovered during the raid.

A 36-year-old man attempted to flee on foot into bushland but was arrested a short time later, with a 52-year-old woman and 47-year-old man also arrested at the scene.

The crop was dismantled and destroyed.

The two men and one woman were charged with drug cultivation offences and refused bail to appear in Parramatta Local Court on Sunday.

In total, 5500 plants and 240 kilograms of cannabis bud with a combined estimated street value of just under $30 million have been seized since the probe was launched in February.

Massive meth haul

The bust comes after the Australian Federal Police revealed a 45kg shipment of methamphetamine was headed for Australia before being uncovered in Hong Kong.

AFP Mexico tipped off Hong Kong colleagues about a suspicious shipment in transit for Melbourne, and local authorities found the drugs hidden in an automatic packaging machine.

The methamphetamine could have caused significant harm if imported into Australia, AFP detective superintendent Patrick Gordon said.

“Unfortunately, these international criminal syndicates care only about lining their pockets, not the irreversible harm they cause,” he said in a statement.

-with AAP