A retired Australian bishop has urged Roman Catholics around the world to sign an online petition to Pope Francis to call a new global council to take effective measures to end the sexual abuse of children in the Church.

Bishop Geoffrey Robinson, a former auxiliary bishop of Sydney who co-ordinated the Australian church's response to the sexual abuse crisis, said only a council of the world's bishops would have the power to make the changes needed.

The new organisation would be akin to the 1962-1965 Second Vatican Council, Bishop Robinson told a news conference in Sydney.

However, this council would focus only on solving the abuse issue, he added.

Bishop Robinson said the Pope had "given out a lot of good signals" since his surprise election in March.

"The petition is not to challenge him, it's to help him, to indicate the people are with him in really looking at these factors and changing whatever needs to be changed," he said.

The scandal of priests molesting minors has haunted the Catholic Church around the world for over two decades.

Bishop Robinson spoke at the launch of his new book, For Christ's Sake: End Sexual Abuse in the Catholic Church - for Good. His petition reached 15,000 signatures.