The World Council of Churches is encouraging its member churches to get involved with the EXPOSED campaign to end corruption.
The global campaign, led by Micah Challenge, highlights that around a trillion US dollars goes missing from the global economy through bribes, dishonest deals and tax evasion - money that could be spent on lifting millions of people out of poverty.
The highlight of the campaign is a week of action from 14 to 20 October, when Christians around the world are being asked to raise their voices against corruption and organise vigils in solidarity with the poor.
The campaign aims to collect at least a million signatures against corruption, which will then be presented at the G20 meeting taking place in November 2014.
"The WCC's concern and response to the issue of corruption is founded on God's preferential option for people in poverty," said Reverend Dr Olav Fykse Tveit, the WCC general secretary.
"Corruption is rooted in and propagated by our prevailing economic structures, cultures and value systems" which are driven by "greed, relentless pursuit of power, profit and material gain by corporations, political bodies, administrators and individual actors".
He added: "Confronting systemic corruption is therefore a matter of upholding God's justice."
The campaign's aims are shared by WCC member churches working to address economic injustice. The WCC's forthcoming assembly in Busan, South Korea, will take place around the theme of "God of life, lead us to justice and peace", and includes a plenary on "overcoming greed".
From 23 to 25 August, the WCC will hold an international panel on New Financial and Economic Architecture in partnership with the World Communion of Reformed Churches, Council for World Mission and the Lutheran World Federation. The panel takes place in Switzerland and will develop advocacy strategies on how to "overcome greed" while working towards a new economic and financial architecture.