Sydney Cardinal George Pell on Friday clarified comments he made that the resignation of Pope Benedict XVI was destabilising, acknowledging the departing Pope's deterioration in health.

"He (Benedict XVI) recognises this represents something of a change in tradition and you could say in a mild way, it destabilises, changes 600 years of tradition," Pell said on Friday.

However he added that Benedict clearly did not look well and had  "deteriorated even in the last couple of months".

Speaking to the Assocaited Press on the first day of the Sede Vacante - when the Vatican is without a Pope, Pell said he hope Benedict's resignation did not lead to " a succession of Popes who resign quickly" and he said he suspected that cardinals would be looking to choose "a somewhat younger person than Cardinal Ratzinger was when he was elected Holy Father...at the age of 78."

Cardinal Pell also addressed the question of the reports of a dysfunctional Vatican curia, the scandal known as Vatileaks in which the Pope's butler was convicted of stealing documents from the Papal apartment and giving them to a journalist.

Pell noted that not all the curia was failing, but the next Pope would have to make some efforts to improve the administration of the Vatican.

"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, " he said.

Benedict's decision to live at the Vatican in retirement, be called "Emeritus Pope" and "Your Holiness" rather than revert back to "Joseph Ratzinger", and wear the white cassock associated with the papacy, has deepened concerns about the shadow he might cast over the next papacy.

He has tried to address those worries over the past two weeks, saying that once retired he would be "hidden from the world" and living a life of prayer.

On Thursday he took a step further with his own public pledge to place himself entirely under the authority of the new pope.