The region's Catholic churches were in celebration mode yesterday following Pope Benedict XVI's acknowledgment of two miracles in Mother Mary's name, which comes a century after her death.

The cause will go to a Solemn Consistory in March, where the Pope will make the final announcement of canonisation and declare a date for a canonisation ceremony in Rome.

Wollongong Catholic Bishop Peter Ingham, who intended to attend the canonisation, said the announcement was "wonderful news".

"I'm overjoyed. It's a great thing, not only for the church but also for Australia because she's one of our national treasures," he said.

"The joy, just at Mass this morning, people are just so delighted. One woman said to me, 'I cried when I heard'."

Bishop Ingham expected an Illawarra contingent to travel to Rome for the canonisation.

He said a committee had been established in Australia to co-ordinate the celebrations in Rome and simultaneous festivities on home soil.

"It will be a big event. The cause of her canonisation started in about 1924.

"It's had a lot of hitches, a lot of difficulties over the years, so this is the culmination of a long, long process."

Bishop Ingham said the Sisters of St Joseph, established by Australian-born Mary MacKillop in 1866, was the second Catholic order of nuns to arrive in the Illawarra, after the Sisters of the Good Samaritan.

Mary MacKillop Place archivist Sister Kath Burford said the sisters arrived in 1880, establishing five Catholic schools over the next decade, at Dapto in 1880, Bulli (1881-1995), Albion Park (1882-1995), Jamberoo-Kiama (1883-1888) and Berry (1889-1978).

"During the period 1960-1980s, the sisters accommodated the increase of migrants into the Illawarra region, and their immediate response and impact on the Catholic school system was by setting up Motor Missions centred at Port Kembla (1965) and Kiama (1969) where they had convents," Sr Burford said.

Sr Anne Derwin, Congregational Leader of The Sisters of Saint Joseph, said Mother Mary was not only "saintly" but "one of Australia's true heroes".

"... she was bold and tenacious and let nothing stand in the way of her care for others.

"The universal recognition of Mary's holiness for the church will inspire future generations both in Australia and throughout the world," she said.