Intrigue at the Vatican could weaken the chances of the next pope being an Italian, observers said, as memos leaked from the Holy See's corridors of power lift the lid on tensions between cardinals.

While revealing deep discord within the Vatican administration, the "Vatileaks" scandal has also shown Pope Benedict XVI's concern with the day-to-day running of the Church despite the 85-year-old's physical frailty.

That has not stopped rumours about a possible successor, however.

A quarter of the cardinals that can elect a new pope are Italian and the general view before the scandal broke was that they would help elect one of their own, reverting to a centuries-long tradition of Italian popes.

The last non-Italian pope before the German Benedict and his Polish predecessor John Paul II was Adrian VI, who died in 1523.

But that logic is looking increasingly improbable as the scandal has created an impression that the Roman Curia is dominated by Italians more concerned with their ambitions than the greater good of the world's 1.2 billion Catholics.

"The side effect of Vatileaks is that it has seriously damaged the prospects for an Italian candidature to the papacy," Marco Politi, a Vatican expert who writes for Italian daily Il Fatto Quotidiano, told AFP.

"Many cardinals and bishops abroad see the incident as an unpleasant Italian affair although it really affects the whole Church," he said, adding: "A lot will depend on whether Benedict XVI can get a firm handle on the situation."

Leaks of confidential memos -- many of them published in a book called "Your Holiness" by Italian investigative journalist Gianluigi Nuzzi -- have thrown into question the role of Vatican Secretary of State Tarcisio Bertone.

The scandal led to the arrest last month of the pope's butler, Paolo Gabriele, as the alleged source of the leaks and has brought public criticism of the increasingly powerful Bertone's leadership from senior Italian clergy.

Vatican watcher Sandro Magister said: "The Roman Curia (the central administration of the Catholic Church) has never had a good image."

Clergy in other parts of the world see it as "a centre of power that creates problems instead of helping. They now find confirmation of this," he said.

The Italian cardinals are "no single bloc," he said, adding that no one candidate among them had emerged as a "convincing" possible successor.

Even the rising star of the hitherto most favoured Italian candidate, the 70-year-old Archbishop of Milan Cardinal Angelo Scola, has been waning.

Scola who has earned plaudits for his dynamism and international initiatives but does not rate highly for his pastoral qualities "has been affected indirectly" by disputes between other Italian cardinals, Magister said.

The expert dismissed as improbable Scola's attempts to distance himself from the influential Catholic movement "Communion and Liberation" which he helped promote but which is now being criticised for its clout in Italian politics.

While papal elections tend to favour "insiders" such as Benedict himself, who headed up the Vatican's Congregation for the Doctrine of the Faith for 24 years, there is now increased interest in possible "outsider" candidates.

One name frequently cited in Vatican circles is that of Canadian cardinal Marc Ouellet, 68, a respected theologian who heads up the world's bishops.

Ouellet speaks several languages and is seen as a "modern conservative" as well as having clout in Latin America -- the world's most Catholic continent.

A similar candidate could be the Archbishop of New York, Timothy Dolan, who at 62 is still relatively young for the Catholic hierarchy and whose rhetoric is seen as more in tune with the modern world than that of other prelates.

Brazil's Joao Braz de Aviz, 64, who is in charge of religious orders at the Vatican, is also respected for his openness and his pastoral qualities.

Ghanian cardinal Peter Turkson, 63, head of the Pontifical Council for Justice and Peace, and Honduran cardinal Oscar Maradiaga, 69, who leads Caritas International, are also sometimes mentioned but are seen as too progressive.

Conclaves -- the meetings of cardinals to elect a new pope -- can of course always have unexpected results. The most famous example? Karol Wojtyla in 1978.