The Catholic Church says it will not follow new Tasmanian laws that require priests to break the seal of confession to report suspicion of child sex abuse.

Key points: New Tasmanian laws make it a criminal offence to fail to report child sex abuse

New Tasmanian laws make it a criminal offence to fail to report child sex abuse Tasmanian Archbishop Julian Porteous says the laws will make paedophiles less likely to come forward

Tasmanian Archbishop Julian Porteous says the laws will make paedophiles less likely to come forward Catholic historian Paul Collins says few Catholics enter the confession booth in 2019 anyway

The Legislative Council yesterday passed Government legislation making religious ministry and MPs mandatory reporters of child sex abuse, along with teachers, police and health professionals.

The laws also require any Tasmanian with knowledge of child sex abuse to report the crime to police — or face up to 21 years' imprisonment or fines of up to $3,360.

But Tasmania's most senior Catholic said the laws would make paedophiles less likely to come forward.

In a statement, Archbishop Julian Porteous said priests were "unable" to follow secular law that required them to break the seal of confession.

"I believe the Tasmanian bill will not strengthen protections for children and vulnerable people, but it will have the opposite effect — as offenders will be less likely to come forward to confess serious sins for fear of being reported," Archbishop Porteous said.

"This will deny priests the opportunity to encourage offenders to report themselves to police."

Beyond Abuse spokesman Steve Fisher said the church needed to enter the 21st century.

"Our question to them is how much damage does it do to the 14-, 15-year-old child who goes into the confession booth asking for help and is then told that no, we won't be doing anything," Mr Fisher said.

"That will further traumatise him or her and he may never come forward again.

Elise Archer says there's no excuse for failure to report the abuse of children. ( ABC News: Peter Curtis )

"They really, really need to look at what is best for survivors instead of what is best for the church."

Attorney-General Elise Archer said the legislation made it clear that all members of the community "must do everything in their power to protect children and prevent child abuse from occurring".

"There is no excuse for failure to report the horrific abuse of children, least of all for institutions who have been named by the Royal Commission as failing to prevent child abuse in the past," she said.

South Australia, Victoria, the Northern Territory and the ACT have passed similar laws requiring religious leaders to report child sex offences.

The law was recommended after the Royal Commission into Institutional Responses to Child Sex Abuse.

Former Hobart priest and Catholic historian Paul Collins said while he personally supported such laws, he did not believe they were effective.

Steve Fisher says the church needs to consider what is best for survivors. ( ABC News: Justin Huntsdale. )

"[That's] for the simple reason that the vast majority of Catholics go nowhere near the confessional, there'd only be a tiny minority of Catholics who use the confessional and I think it extraordinarily unlikely that any person who has committed paedophilia would be going to confession," Dr Collins said.

"It'd be very difficult to enforce these laws for the simple reason the priest will say nothing because he's bound by the seal of confession, and presumably the paedophile will not be broadcasting abroad what he's said in confession."

Archbishop Porteous said Tasmania's new laws seemed at odds with the Federal Government's religious freedom push.

"The Catholic Church in Tasmania is committed to safeguarding children and the vulnerable. It is continually working to ensure that priests and all who work for the Church understand their obligations before the law to report on matters of child sexual abuse," he said.

"The Catholic Church fully supports the role of police and the courts in bringing perpetrators of abuse to justice."