Pope Benedict XVI has officially recognised Australia's first saint, Mary MacKillop, a Melbourne-born nun who worked with needy children.

She was canonised with five others, including Brother Andre, a Canadian monk credited with miraculous healings.

MacKillop, who died in 1909, clashed with senior clergy and was briefly excommunicated, in part for exposing a sex-abusing priest.

Thousands of Australians are in Rome to witness the ceremony.

Among them are hundreds of nuns from the order MacKillop helped found, the Sisters of St Joseph of the Sacred Heart.

"We've always believed that Mary was a saint," said 65-year-old Moya Campbell, a member of the order.

Father Thomas Casanova, a Catholic priest from New South Wales and a distant relative of MacKillop, said it was a momentous occasion.

"I've been looking forward to this since I was a child. She will help us have a greater perspective on life," he said.

Others wanted to recognise MacKillop's lifetime of commitment to working with poor people, including Australia's Aboriginal population.

"She supported Aboriginal people because she believed in supporting people who were disadvantaged," said pilgrim Melissa Brickell.

"She sought social justice for Aboriginal people, so she is a friend of Aboriginal people from the early, early days."

Mary MacKillop was excommunicated in 1871, but the Church later exonerated her and she was eventually put on the road to sainthood by Pope John Paul II, who beatified her in 1995.

Australian Foreign Minister Kevin Rudd, also among those at the ceremony, has described MacKillop as "an extraordinary Australian woman".

Religious celebrity

For anyone to become a saint, the Church has to officially recognise their intermediary role in two miracles.

Pope John Paul II recognised the first, and last year Pope Benedict ruled a person had been cured of cancer after praying for the nun's assistance.

Because of her role in exposing clerical abuse, some have called for MacKillop to made a patron saint of abused children.

In recent years, there has been a wave of cases around the world in which Church authorities failed to deal properly with priests accused of child abuse, sometimes just moving them to new parishes where more children were put at risk.

MacKillop has become a kind of religious celebrity in Australia, where there is great anticipation about her canonisation, says the BBC's Duncan Kennedy in Rome.

She has been the subject of a musical, has stamps and pop songs in her honour and her image has been projected onto Sydney's Harbour Bridge.

Thousands of people have attended a Mass in Melbourne's St Patrick's Cathedral to mark her passage to sainthood.

And all week, pilgrims have been converging on the chapel and museum at the site in North Sydney where she died, says the BBC's Nick Bryant in Sydney.

Candidates from Canada, Poland, Italy and Spain are also being officially recognised as saints at the Vatican ceremony.

Four steps to sainthood

The process, which cannot begin until at least five years after the candidate's death, involves scrutinising evidence of their holiness, work and signs that people are drawn to prayer through their example:

    * First stage: individual is declared a 'servant of God'
    * Second stage: individual is called 'venerable'
    * Third stage (requires a miracle attributed to candidate's intercession): beatification, when individual is declared blessed
    * Fourth stage (requires a further authenticated miracle): candidate is canonised as a saint for veneration by Church