The General-Secretary of the Australian Catholic Bishops Conference, Fr Brian Lucas, said Prime Minister Kevin Rudd's enthusiasm for the canonisation of Mary MacKillop was "welcome".
"There is a strict and detailed protocol for assessing a cause for canonisation," he said in a press statement. "That is administered by the Congregation for the Causes of Saints and it is not open to any external influences.
"However, the Holy Father would be very interested to hear from the Prime Minister about the enthusiasm with which the canonisation of Blessed Mary MacKillop would be received in Australia, including among those who are not Catholics."
A spokesman for Mr Rudd said that before his audience with Pope Benedict, the Prime Minister will be briefed by Sr Maria Casey, who would explain her work with the Vatican's Congregation for the Causes of Saints to progress the cause towards recognition of Mary MacKillop as the first Australian saint.
"While acknowledging that canonisation is a process internal to the Church, Mr Rudd is expected to express that many Australians are inspired by Mary MacKillop's example," the spokesman is quoted saying.
Fr Frank Brennan is quoted by The Australian as disagreeing with media criticism that the Prime Minister was out of place in discussing Mary MacKillop's canonisation with the Pope.
"I can't see how anyone would see it as a lobbying exercise," Fr Brennan said. "I would think that it would be a matter of high diplomacy. I can't imagine one of Mr Rudd's character crossing that line.
"Anything that crossed that line would risk being seen as crass and counter productive. I'm pretty confident that Mr Rudd wouldn't cross it."
Sister of St Joseph, Mary Ellen O'Donoghue said Mr Rudd's visit to Rome "would not make any difference" to the process of canonisation.
"What I think the Pope's reaction will be is that the Prime Minister's visit will underscore that this event is a very significant event for the Australian people," she told The Australian.
Media release (Australian Catholic Bishops Conference)
Church backs Kevin Rudd's motives on Mary MacKillop sainthood (The Australian)
Sisters of St Joseph
Mary MacKillop (Wikipedia)
Rudd to petition Pope on MacKillop sainthood
Rudd's Mary MacKillop pitch is spin gone mad: Abbott