Two arrested in $60m Sydney MDMA bust

More than half a tonne of crystal MDMA, worth around $60 million, has been seized and two men charged in a "extremely sophisticated" attempt to smuggle the drug into Sydney.

More than 500kg of the drug, which equates to around 1.7 million ecstasy tablets, was discovered at Port Botany in October hidden inside a shipment of aluminium sheeting from Italy.

In a bid to avoid x-ray detection the drugs were enclosed in lead-lined cylinders inside tightly wrapped rolls of aluminium, Australian Border Force NSW regional commander Tim Fitzgerald said on Tuesday.

"This is a complex concealment and this is an importation that has been organised by international crime syndicates," Mr Fitzgerald said.

Following the discovery the Australian Federal Police organised a controlled delivery, which led them to arrest two Chinese nationals and raid several premises including a storage facility in Miranda on Sunday.

The men, aged 38 and 34, were a "significant part" of an importation syndicate and further arrests are expected, AFP acting commander Brett James said.

The haul is the fifth largest MDMA seizure in Australia and one of the largest this year, Mr James said.

"A significant seizure such as this has a huge impact on the supply of MDMA," he said.

The rise in large-scale drug importation is an ongoing trend and in the past two years police had intercepted 12.5 tonnes of narcotics, Mr Fitzgerald said.

"We are seeing large amounts of drugs attempting to be imported into this country," he said.

Both men have been refused bail and will face Sydney Central Local Court in February.