More than 100 organised crime members have been arrested in Australia as part of the operation, initiated after the United States’ FBI decrypted “Anom”, an online communications platform used by gang figures.

The communications found on the platform included 21 murder plots, gun distribution and mass drug trafficking, federal police say.

The operation is three years in the making.

Australian Federal Police said on Tuesday it had seized 3.7 tonnes of drugs, 104 weapons and almost $45 million in cash as part of the operation.

Offenders are linked to the Australian-based Italian mafia, outlaw motorcycle gangs, Asian crime syndicates and Albanian organised crime figures.

Prime Minister Scott Morrison said the AFP operation, known as Operation Ironside, had struck a “heavy blow” against criminals.

“The operation puts Australia at the forefront of the fight against criminals who peddle in human misery and ultimately, it will keep our communities and Australians safe,” he told reporters on Tuesday.

“Illicit drug use ruins lives and fuels organised crime.”

New Zealand authorities have also arrested 35 people for alleged drug dealing and money laundering, seizing some $NZ3.7 million ($A3.4 million) in assets.

OPERATION IRONSIDE – WHAT WE KNOW

* Operation Ironside is the name of the Australian Federal Police arm of a global covert investigation, involving the US Federal Bureau of Investigation and Europol.

* It began almost three years ago.

* It targeted an encrypted communications platform used by organised crime gangs around the world.

* The platform was an app called ANoM, installed on stripped-back black market mobile phones that could only send messages to another device.

* Criminals needed to know a criminal to get one.

* The devices grew in popularity among criminals after high-profile figures – dubbed “criminal influencers” – vouched for them.

* But ANoM was being covertly run by the FBI, allowing law enforcement to piggyback chatter between gangs.

* The encrypted communications included plots to kill, mass drug trafficking and gun distribution.

* In Australia, the alleged perpetrators include the Italian mafia, outlaw motorcycle gangs, Asian crime syndicates and Albanian organised crime figures.

* More arrests are expected domestically and offshore under a coordinated global response connected to Operation Ironside.

WHAT HAS THE OPERATION TURNED UP IN AUSTRALIA SO FAR?

* Some 224 Australians have been arrested and more than 100 charged in every mainland Australian state.

* Seizure of 3.7 tonnes of drugs, 104 weapons, about $45 million in cash and assets expected to run into the millions of dollars since 2018.

* The AFP has also acted on 21 direct threats to kill, potentially saving the lives of a significant number of bystanders.

INVOLVEMENT OF OTHER LAW ENFORCEMENT AGENCIES

* The European Union police agency, Europol, and the FBI will hold their own press conferences on Tuesday and into Wednesday Australian time.