But a joint investigation by the Fairfax media group and the ABC television program 7.30 has uncovered more evidence of corruption - this time on Australia's waterfront.
Correspondent: Martin Cuddihy
Speakers: Ross Fusca, former Victorian-based AFP officer; Clive Small, former New South Wales assistant police commissioner
MARTIN CUDDIHY: For years there have been rumours of corruption at Port Botany. In 2008 police discovered an influential stevedore driving a Porsche and making massive cash withdrawals.
In this story he's known as Mr X, for legal reasons.
ROSS FUSCA: We were aware of dockworkers that were living beyond their means and clearly Mr X was. When expenditure outweighs income that is a clear indicator to any law enforcement officer that the particular person that they're investigating is accumulating wealth outside his normal form of employment and clearly you would target that person.
MARTIN CUDDIHY: The Polaris taskforce was set up to investigate Mr X and others like him. A joint Fairfax/7.30 investigation uncovered this secret report from earlier this year.
EXTRACT FROM REPORT: Polaris investigations have identified employees of law enforcement and regulatory bodies providing assistance to criminal groups. The employees have included members of Customs and employees of the Australian Quarantine and Inspection Service.
MARTIN CUDDIHY: Former New South Wales assistant police commissioner Clive Small:
CLIVE SMALL: The fact of the matter is that these contacts on the wharves are really middle men. They are part of a broader network. But their role is not to deal with the drugs directly but to simply provide information, provide a supervision of drugs. Or if a container has landed and is known to contain drugs they keep an eye on it. Do they see Customs or police or anyone else going near it?
MARTIN CUDDIHY: Sources have told the Fairfax/7.30 investigation that Customs paperwork has been fraudulently filled out, giving the all-clear to containers that may have been filled with illegal handguns. The pistols are suspected to have been smuggled in shipping containers which Customs officers claimed they had x-rayed when they hadn't
They could be the same guns used in the scores of illegal Sydney shootings.
At least a dozen Customs staff are suspected of corruption or at the least serious misconduct.
Ross Fusca is a former Victorian based AFP officer.
ROSS FUSCA: It's my understanding that there are still quite a number of people that work for stevedoring companies and other agencies that can and will assist in the removal of shipping containers.