Pope Francis Scampia
Pope Francis addresses crowds in Scampia, Naples. Filippo Monteforte/AFP

Pope Francis condemned corruption and criminality, urging residents not to lose their hope on a visit to a mafia dominated area in Naples.

On a trip to the notorious Scampia neighbourhood of the southern Italian city, where drugs are dealt openly and unemployment stands at 40%, Francis drew crowds of thousands.

"Corruption stinks, corrupt society stinks," he told residents, adding that "we all have the potential to be corrupt and to slip into criminality", reports AFP.

Rival gangs battle in the area for control of lucrative drug trading and extortion rackets.

Francis implored the residents to retain hope despite pervasive corruption and criminality.

"See to it that evil is not the last word. It (the last word) has to be hope," he said, according to Reuters. "Those who voluntarily take the road of evil rob a piece of hope. They rob it from themselves and from everybody, from society, from so many honest and hard-working people, they rob it from good name of the city and from its economy."

In a speech last year in Calabria the Pope condemned organised crime and excommunicated all members of the mafia.

In Naples, Francis defended the rights of immigrants, declaring they should not be considered "second-class human beings", called for fair wages for workers and railed against corruption.

"How much corruption there is in the world! I hope you have the courage… to clean up the city and clean up society so that there is no longer that stink of corruption," he said.

Later, Francis ate a meal with inmates in a notorious local prison, and said a Mass in the city's centre.