Pope Benedict XVI has blamed greed and selfishness for the global financial crisis, in his latest encyclical.
On the eve of the G8 summit in Rome, the 144-page document is intended to remind world leaders, bankers, business people and the public of their moral duties.
The letter, "Caritas in Veritate" or "Charity in Truth", is the third since Benedict became Pope in 2005.
He told a group of priests in Rome earlier this year he did not want to give simplistic answers to complex questions concerning the world economy.
But he has now singled out human greed and selfishness as the root causes of the economic crisis.
Pope Benedict said on Tuesday every economic decision had a moral consequence. He called for "forms of redistribution" of wealth overseen by governments to help those most affected by crises.
He said "there is an urgent need of a true world political authority" whose task would be "to manage the global economy; to revive economies hit by the crisis; to avoid any deterioration of the present crisis and the greater imbalances that would result".
Such an authority would have to be "regulated by law" and "would need to be universally recognized and to be vested with the effective power to ensure security for all, regard for justice, and respect for rights".