West Australian police say $1.8 million cash seized during a traffic stop in Southern Cross last week is suspected to be the profits of organised crime and drug trafficking, although investigations are ongoing.
The Transnational and Serious Organised Crime Squad has charged a 36-year-old man with property laundering.
It was alleged the man hired a vehicle and was travelling from Perth to the eastern states when he was stopped on the Great Eastern Highway near Southern Cross on Thursday afternoon.
Police alleged officers found a large suitcase in the boot of the car, which contained the cash inside a duffel bag.
The squad's Detective Sergeant Steve Carter described the cash as a "significant seizure".
"It's still subject to investigation, the origins of the cash and where it came from," he said.
"Simply the manner in which it was packaged, how it was getting taken to the eastern states, obviously the inference is that it was coming from organised crime activity in Western Australia and that's something we're pursuing in our investigative actions.
"I can't comment any further about that at the moment, but it's something we're definitely looking at."
Detective Sergeant Carter said officers acted on information from the Australian Criminal Intelligence Commission.
"Any disruption to the money flow, which is the key motivator for organised criminals … is important and significant," he said.
"Investigations are at the very infancy, and we're following up on all sorts of investigative actions, in relation to this man being in Western Australia, what he got up to in [the state] and, ultimately, where he was going."
He said more charges were possible as it was "highly likely" others were involved.
"A seizure of this nature, it's highly likely that others are involved, and a key aspect of our investigation is to identify anybody, anywhere in Australia who was involved in this [alleged] criminality in Western Australia," Detective Sergeant Carter said.
The 36-year-old man has been granted bail and is due to reappear in the Perth Magistrates Court on June 16.