Pope Benedict XVI has given his final public audience before tens of thousands of enthusiastic people who thronged to bid farewell to him in St. Peter's Square at the Vatican.

Cheered on and applauded by the big crowd Benedict said, "I will continue to accompany the Church with my prayers, and I ask each of you to pray for me and for the new Pope.

"In union with Mary and all the saints, let us entrust ourselves in faith and hope to God, who continues to watch over our lives and to guide the journey of the Church and our world along the paths of history."

The Pope, who turns 85 in April, stunned many of the world's 1.2 million Roman Catholics when on Feb. 11 when he announced he would resign from the end of February.

Citing his age and health Benedict becomes the first pope to voluntarily resign in 600 years.

Benedict said, "To love the Church also means having the courage to take difficult decisions, bearing always in mind the good of the Church and not of oneself."

The Vatican issued around 50,000 tickets to the square, but many thousands more thronged the area outside that area and the crowd was estimated at 150,000.

He recollected when he became Pope in April 2005 alluding to his message then when he said that whoever assumes the papacy "no longer has any privacy. He belongs always and totally to everyone, to the whole Church."

The Pope noted, "My decision to forgo the exercise of active ministry, does not revoke this. I do not return to private life, to a life of travel, meetings, receptions, conferences and so on. I do not abandon the cross, but remain in a new way near the Crucified Lord."

He added, "I no longer wield the power of the office for the government of the Church, but in the service of prayer I remain, so to speak, within St. Peter's bounds. St. Benedict, whose name I bear as Pope, shall be a great example in this for me. He showed us the way to a life which, active or passive, belongs wholly to the work of God."

As a retiree from the papacy Benedict will be called "Pope Emeritus," or the "Supreme Roman Pontiff Emeritus" or "Your Holiness," and he will still wear white the Vatican said on Tuesday.

But he will no longer wear his distinctive red shoes, swopping them for a brown pair he was given on a trip to Mexico. Benedict will live on the Vatican grounds in an apartment that is being renovated.

Along with the Pope's resignation concerns have arisen about clerical abuse scandals that existed under predecessor Pope John Paul II, continuing to do the papacy of Benedict that did not reach the type of closure demanded by victims and their supporters.

The decision by the Britain's most senior Catholic cleric, Cardinal Keith O'Brien on Monday not to attend the conclave to elect a new pope following allegations he behaved in an "inappropriate" way with other priests soured the build-up to the conclave.

O'Brien's decision was made when a number of cardinals tainted with claims that they failed to remove priests accused of sexually abusing minors will be among the clergy getting ready for the conclave.

On Thursday, at his last day of the papacy, Benedict will say farewell to his cardinals who will start the process to elect his successor.

The 115 cardinals have to meet within 15 to 20 days of the Pope's last day, but can meet sooner with a new decision made on this by Benedict.

There is speculation that the new pope could come from Africa or Asia, where the church is growing.