POPE Francis has told UN Secretary General Ban Ki-moon the world body must do more to help the poor and should encourage the "legitimate redistribution" of wealth.

Francis, who since his election last year has often called for significant changes to economic systems, made his comments in an address to Ban and heads of many UN agencies meeting in Rome.

"In the case of global political and economic organization, much more needs to be achieved, since an important part of humanity does not share in the benefits of progress and is in fact relegated to the status of second-class citizens," Francis said.

Francis, an Argentine, is the first non-European pope in 1300 years and the first-ever Latin American pontiff. He has consistently used his meetings with world leaders, including US President Barack Obama in March, to champion the cause of the world's have-nots.