CANBERRA (DPA) - Australian authorities have seized almost 1.6 tonnes of illicit methylamphetamine in Melbourne in the biggest ever onshore seizure of the drug commonly known as Ice.

Australian Border Force (ABF) officers discovered the drugs in vacuum-sealed packages hidden inside stereo speakers in a sea cargo consignment originating from Thailand's capital Bangkok.

In total, 1.596 tonnes of methylamphetamine and 37kg of heroin were detected, the Australian Federal Police (AFP) said in a statement on Friday (June 7).

The seized quantity amounts to almost 16 million drug deals with an estimated street value of A$1.2 billion (S$1.1 billion), the statement said.

There have been no arrests made and the authorities are continuing with the investigations.

"This is the largest meth bust we've ever seen in this country and demonstrates... the brazen nature of those involved in this criminal activity," ABF Regional Commander Craig Palmer said.

He added that the seizure amounts to more than 13 per cent of the total drugs seized by the authorities since July 2018.

In April, Australian authorities seized more than half a tonne of Ice, worth more than A$438 million, hidden in commercial refrigerators imported from Singapore.

Australian authorities in the past have said the country has a "serious epidemic" of drug use with an "insatiable demand" for illicit substances.

In February, an analysis of waste water data found Australians spent about A$9.3 billion on illicit drugs in a year, with an estimated 9.6 tonnes of methylamphetamine consumed.