Pope Francis arrives to celebrate a mass at the monument to Mary, Queen of Peace in Mauritius. Reuters

Pope Francis was welcomed by palm frond-waving crowds in Mauritius on Monday as he drove past sugarcane fields on his way to the capital, where he said a Mass on a terraced mountainside overlooking the harbour.

Tens of thousands of people gathered to see the pontiff on his lightning visit at the end of a three-country tour of Africa. He was due to spend about eight hours on the Indian Ocean island.

Pope Francis (centre) arrives to lead a mass at the Monument of Mary Queen of Peace, Port Louis, Mauritius. AFP

Mauritius is far richer than the first two countries on his tour — Mozambique and Madagascar — as the former British colony has benefited greatly from tourism and a financial services sector.

But it also has a youth unemployment problem and a sizable income gap between social classes, and the pope addressed both issues in the homily of his Mass.

"Despite the economic growth your country has known in recent decades, it is the young who are suffering the most," he said.

"They suffer from unemployment, which not only creates uncertainty about the future, but also prevents them from believing that they play a significant part in your shared history. Uncertainty about the future makes them feel that they are on the margins of society; it leaves them vulnerable and helpless before new forms of slavery," he said.

Faithfull attend a mass led by the Pope (unseen) at the Monument of Mary Queen of Peace, Port Louis, Mauritius. AFP

Roughly one in four young Mauritians are out of work, and the World Bank says household income inequality there has widened since the global economic downturn after 2008. Only recently has it begun to narrow slightly, according to local statistics.

Anti-poverty campaigners say Mauritius' tax treaties and financial services industry facilitates tax avoidance, draining desperately needed revenues from poor countries.

The main reason for Francis' trip was to pay tribute to Jacques-Désiré Laval, a 19th century French priest who helped former slaves.

Francis returns to Madagascar for the night and leaves for Rome on Tuesday morning.

Reuters