Although the prophet Isaiah "wasn't a communist", wealth and power, when used for selfish gain can be instruments of death, said Pope Francis on Wednesday.

Speaking to his general audience in St Peter's Square, Pope Francis said: "Wealth and power are realities that can be good and useful to the common good if placed at the service of the poor, and of everyone, with justice and charity.

"But when, as too often happens, they are experienced as privilege, with selfishness and arrogance, they are transformed into instruments of corruption and death," he said.

While referring to Isaiah 5, Pope Francis made an impromptu remark, saying: "the prophet Isaiah wasn't a communist!"

The Pope's political persuasion has often been commented on, from critics and supporters alike. He has rejected political labels, opting instead for a focus on the Gospel message to serve the poor.

Referencing Jesus' teaching on servant-hearted leadership in Matthew 20:25-27, Pope Francis said: "If the dimension of service is lost, power is transformed into arrogance and becomes domination and oppression."

During his audience, he also referred to the story of Naboth, in Kings, who was killed by a King who unjustly desired his land, highlighting the message's relevance today:

"It's the story of human trafficking, of slave labor, of poor people that work 'in black' ('under the table') and with the minimum salary to enrich the powerful!

"It's the story of corrupt politicians who want more and more and more!"