Parties reap cash from developers, miners
The property and mining industries have been the most generous contributors to the $1 billion given to political parties.
The Greens' Democracy for Sale website has categorised $995 million in donations between 1998 and 2015, with reported payments expected to top $1 billion in the 2015/16 financial year.
According to the analysis, the property industry has been the most generous sector chipping in more than $64 million, while resource companies had contributed almost $51 million.
Financial and insurance companies provided a further $37 million, while a rise in political interest among pharmaceutical and health organisations has led to $12.6 million being tipped in to party coffers.
The top two donors were Labor Holdings ($41 million) and the Liberal Party investment vehicle Cormack Foundation ($39.2 million).
Former politician Clive Palmer's Queensland Nickel, which bankrolled the Palmer United Party, came in third at $21.7 million, while Mr Palmer's Mineralogy also contributed $15 million.
The website shows a clear spike in donations in election years, dropping off in the two subsequent years.
The most lucrative year was 2013-14 when $114 million flowed into parties and Tony Abbott trounced Kevin Rudd at the polls.
Defence industry donations peaked in the lead-up to the invasion of Iraq in 2003 and energy company donations increased in 2014 while the government considered reform of the sector.
Greens spokesperson for democracy Lee Rhiannon said the system encouraged a "cosy relationship" between vested interests, wealthy donors and political parties.
"While we have donations laws in this country that allow enormous sums of money to flow from vested interests into the coffers of political parties, our democracy is severely compromised," Senator Rhiannon said.
She said stricter caps on donations and election spending were needed.