Australian politics has been significantly undermined by the Italian mafia, according to a joint investigative report conducted by the country's media, which claim that the criminal group used political donations as a means to legitimizing its activities.

A report from the Australian Broadcasting Corporation and Fairfax Media found that the Calabrian Mafia, also known as 'Ndrangheta -- known to be active in operating drug trafficking and extortion rings as well as some legitimate businesses -- used donations to leading political parties to cover up their illegal activities in the country. Australia is currently dealing with a major drug-trafficking problem, which the Tony Abbott government has blamed on transnational groups.

The 'Ndrangheta is considered one of the world’s most powerful criminal groups. It is estimated to have made almost $60 billion in revenues in 2014, through illegal activities such as drug trafficking, and also legal and illegitimate business ventures, including fruit sales and garbage disposal services. Their earnings are thought to have made up almost 3 percent of Italy's GDP in 2014.

The investigation found several links between known and suspected criminals, and senior Australian politicians. The report said that a man with "deep mafia associations" met with former prime minister John Howard and other members of his conservative Liberal Party of Australia at a fundraiser in the early 2000s. However, the report did not suggest that Howard knew of the connection.

The report also alleged that the son of another mafia boss reportedly worked at the Australian embassy in Rome. Prior to his placement, Italian authorities shared sensitive information about the alleged criminal leader through the embassy, at a time when former Liberal minister Amanda Vanstone was ambassador to Italy, according to the report. There was no suggestion that Vanstone knew of the criminal links either, or that the placement resulted in a security breach.

Vanstone is also being investigated for granting a visa --  while she served as immigration minister in Howard’s administration-- to alleged crime boss Francesco Madafferi -- who was later convicted of drug trafficking and implicated in a murder plot.

Madafferi reportedly has an extensive criminal history in Italy. He was set to be deported, but a lobbying campaign on his behalf led to him being supported by four Liberal lawmakers, resulting in him being granted a visa in 2005. There was no suggestion that Vanstone acted improperly in this incident either.

According to a confidential 2009 report from the Australian Federal Police (AFP), cited by the ABC, the infiltration of the government was allowed to happen because of a “lack of checks and oversight.”

"As it stands, political parties and candidates can receive significant support and financial contributions through avenues not covered by the statutory disclosure regime," the AFP report said.

The report also said that Australia’s electoral commission has tried to address the issue many times but amendments that would take on the political donations issue have failed to pass the country’s parliament.

The results of the investigation are expected to be broadcast on Australian television Monday. Lawyers representing an unnamed Melbourne businessman, allegedly linked to the mafia, have sought an injunction seeking to stop the program from airing, ABC reported.