Pope Francis criticised the wealth made from financial speculation on Monday as "intolerable" and said speculation on commodities was a "scandal" that compromised the poor's access to food.

Since his election in March 2013, Francis has often attacked the global economic system as being insensitive to the poor and not doing enough to share wealth with those who need it most.

Addressing a seminar on ethical investing in the Vatican on Monday, he said financial markets must serve the interests of the people and the common good of humanity.

"It is increasingly intolerable that financial markets are shaping the destiny of peoples rather than serving their needs, or that the few derive immense wealth from financial speculation while the many are deeply burdened by the consequences," he said.

He has previously decried a system he said was based on "a god called money," called for the redistribution of wealth and used many speeches to bring attention to the social problem of high unemployment.

"Speculation on food prices is a scandal which seriously compromises access to food on the part of the poorest members of our human family," he said on Monday.

"It is urgent that governments throughout the world commit themselves to developing an international framework capable of promoting a market of high impact investments, and thus to combating an economy which excludes and discards," he said.

Markets had to look for "timely and realistic strategies to ensure greater social equality," he said.

He threw his support behind so-called "impact investment," a trend that looks for opportunities for investors to make positive social and environmental change and reinvest moderate profits in other ethical ventures to help communities.

Ethical investment was logical for religious believers because it "acknowledges the ultimate connection between profit and solidarity, the virtuous circle existing between profit and gift", he said. - Reuters