A pro-same-sex-marriage priest was banned by the Catholic Archbishop of Hobart from speaking at an event earlier this year due to his views on marriage equality.

Father Frank Brennan, a Jesuit academic and head of Catholic Services Australia, had been invited to speak at a CatholicCare Tasmania conference in February.

Father Frank Brennan said the Tasmanian Catholic Archdiocese "don't want me coming". ( ABC 7.30 Report )

A spokesman for the Archdiocese confirmed Archbishop Julian Porteous felt it was inappropriate for Father Brennan to speak at the conference, due to his public position advocating strongly for religious freedom on the issue of same-sex marriage.

"Archbishop Porteous addressed the conference on the issue of marriage. His Grace felt it was inappropriate for Father Brennan to speak at the conference, due to his public position regarding same-sex marriage," the spokesman said.

Father Brennan has argued Catholic priests should be allowed to vote on same-sex marriage as a matter of conscience.

The conservative Archbishop Porteous has been a strong campaigner against marriage equality.

It is unclear whether Father Brennan will be able to speak at future Catholic events.

"Yes, I understand they don't want me coming to the Archdiocese," Father Brennan said.

The spokesman for the Archdiocese of Hobart said there was "no ban in place" but he did not respond to a question as to whether Father Brennan would be permitted to speak at, or attend future church events, in the Archdiocese.

Brennan not a 'raging radical': commentator

Former Catholic priest Paul Collins said it was an "extraordinary decision".

"It is not as though Frank were some raging radical, he is a person who runs all of the Catholic Church's social services in the country," he said.

Mr Collins said Archbishop Porteous was out of touch with mainstream Catholics.

"Frank Brennan's views on same-sex marriage are absolutely the views of the majority of Catholics in Australia. I voted yes," he said.

"All the evidence points to the fact that the vast majority of Catholic's voted 'yes' and a number of the other Catholic bishops voted 'yes'.

"I think that he [Archbishop Porteous] is out of tune with the mainstream of the Catholic Church.

Mr Collins said Australia was a pluralistic democracy, "and in a pluralistic democracy, people are able to express their views in public".

"What it does is reinforce the notion that bishops live, somehow or other, in cloud cuckoo-land."

Mr Collins said he himself had been banned from the Archdiocese of Sydney, and some of the smaller dioceses.

Bishops have the power to ban people from speaking on church grounds in their Archdiocese.