Pope Benedict XVI arrived in Australia on Sunday, saying he wants to use his visit to raise awareness about global warming and address the crisis of clergy sexual abuse.
Benedict suggested to reporters on the flight from the Vatican that he would express regret about abuse by priests, though victims' groups are demanding he go further and make a direct formal apology.
The clergy abuse scandal is a serious note in the pope's 10-day visit to Australia, his first, during which he will join the World Youth Day festival that has attracted more than 200,000 people.
Benedict, 81, flew more than 20 hours from the Vatican to touch down at a military air base on Sydney's outskirts. He waved briefly as he climbed down the plane's stairway and was greeted on the tarmac by Prime Minister Kevin Rudd and other church and government officials.
He was driven to a retreat in Sydney where he will stay out of the public eye until the youth festival formally begins Thursday.
During the flight, Benedict told reporters he would work for "healing and reconciliation with the victims" of sexual abuse by Roman Catholic clergy in Australia "just as I did in the United States."
At the start of a U.S. visit earlier this year, Benedict said he was "deeply ashamed" of the abuse scandal and pledged to work to make sure pedophiles do not become priests.
Clergy abuse support groups in Australia have demanded that Benedict apologize during his visit for the abuse they suffered. The exact number of victims of clergy abuse in Australia is not known, though activists say it is in the thousands.
Bernard Barrett, a spokesman for the victims' group Broken Rites, said Benedict's comments did not go far enough.
"He made some general remarks about regret to reporters and that's not good enough," he told Australian Broadcasting Corp. radio. "We want action, not words."
"The pope must apologize for the way his Australian bishops have covered up sexual abuse, the pope must tell his Australian bishops to stop blocking victims' access to justice in the civil law courts," he said.
On the plane, Benedict acknowledged the church in the West was "in crisis" but insisted it was not in decline. "I am an optimist" about its future, he said.
Asked about global warming, the pope said there is a need to "wake up consciences" about the issue.
"We have to give impulse to rediscovering our responsibility and to finding an ethical way to change our way of life," he said. Politicians and experts must be "capable of responding to the great ecological challenge and to be up to the task of this challenge," he added.
The Australian trip is the longest in his three-year-old papacy and will test the pontiff's stamina.
Although aides say the pope is in fine health, the Vatican appeared to be taking no chances to ensure Benedict is fit for World Youth Day, canceling a weekly public audience last week and most other meetings so he could rest.
After he succeeded John Paul, Benedict said he doubted he would make many long trips. But invitations keep coming in from world leaders and officials of his global 1 billion-member flock. He visited Brazil last year, traveled to the United States in April and is to visit France in September.
Benedict is to be greeted at Sydney Harbor on Thursday by a group of Aborigines and other young people, and deliver what is expected to be an important address. In 2001, John Paul issued a formal apology to the indigenous peoples of Australia, New Zealand and the Pacific islands for injustices perpetrated by Roman Catholic missionaries.
Benedict will then tour through Sydney in a parade that is expected to shut down most of the downtown district. He will join a crowd expected to total 200,000 at a vigil before leading a Mass next Sunday at the culmination of the festival.
Australia's senior Roman Catholic leader, Cardinal George Pell, has been accused of badly handling a sexual abuse claim and this week agreed to reopen investigations into the 25-year-old case.