Australian police have arrested a man they allege was behind a failed drug import plot that resulted in mysterious cocaine bricks washing up on east coast beaches for months. 

A 36-year-old Queensland man is allegedly the head of a crime network and played a key role in the collection and distribution of tonnes of cocaine across the country, Australian Federal Police said on Thursday. 

But the man's criminal actions unravelled when 900 kilogrammes (almost 2,000 pounds) of cocaine was unable to be collected at sea. 

Police allege the cocaine was then intentionally dropped into the ocean. The drugs had an estimated street value of $617m.

About 256 kilogrammes of that product washed up in bricks on the shores of popular beaches from late 2023. 

The man was arrested on Wednesday and hit with 19 charges. He could face life imprisonment if found guilty.

Australian Federal Police Superintendent Adrian Telfer said the origin of the drugs was still under investigation. 

“There was understandably community concern when cocaine washed up on beaches – beaches where our children play, swim and eat," he said.

"The Australian Federal Police and our partners dedicated a significant amount of resources to ensure we have kept the public safe and brought those allegedly responsible before the courts.”

The drugs were intentionally dropped off at sea, and ended up washing up on Brisbane beaches. Photo: Australian Police Force

He said the man's arrest would be a "signifcant disruption" to Australia's drug trade, including organised crime. 

“Since November of just last year, we will allege he had an intention of importing drugs into Australia on 20 separate occasions, totalling more than 20 tonnes.”