VATICAN CITY: The Catholic church doesn't need "the successor of Peter popping in and out," Australia's cardinal said Friday as questions were raised about what impact Benedict XVI's resignation will have on the choice of his successor.

As Benedict's papacy is officially over, cardinals are starting to raise issues that will take center stage at the conclave where they will gather to elect the new pope. The resignation of a pope and the governing of the church are emerging as topics of debate.

Cardinal George Pell told The Associated Press in an interview that "I hope we don't move to a succession of popes who resign quickly."

Pell was expanding on an earlier statement that Benedict's decision to resign was "slightly destabilizing."

"The instinct I suspect of a number of cardinals would be to look at a somewhat younger person than Cardinal (Joseph) Ratzinger was when he was elected holy father at the age of 78," Pell said.

Despite his worry about the impact of the resignation, Pell said that "you only have to look at him (Benedict) to see how sick he looks. He has deteriorated even in the last couple of months."

In a separate interview, Cardinal Timothy Dolan of New York said Thursday that Pell probably meant that, like himself, the resignation "kind of shook us and startled us because we are not used to it."

"A pope dying is natural - a pope stepping aside is something new to us. So it was startling," he added.

Another American cardinal, Sean O'Malley of Boston, said "it is a whole new ball game after this resignation" but "it is very difficult to forecast how it will play itself out."

O'Malley did suggest the cardinal electors might decide to elect an older man "realizing that he is not going to have to carry this burden on into his 90s and that if he becomes incapacitated," he could resign - in line with Benedict's explanation that he was no longer up to the task.

Pell and others have raised the problem of governance in light of the scandal over leaks of Vatican documents by the pope's butler and the need to tighten procedures in the Curia, the central offices of the church.

"It would be useful to have a pope who can pull the show together, lift the morale of the Curia, and strengthen a bit of the discipline there and effectively draw on all the energies and goodness of the great majority of the people in the curia," Pell said.