The Catholic Church of Australia has threatened to fire staff who wed their same-sex partner if gay marriage is legalised in the country.
The country's most senior Catholic, Archbishop of Melbourne Denis Hart, told the Sydney Morning Herald the church's 180,000 employees were expected to "totally" uphold its teachings.
The church "shouldn't be slipping on that", he said.
"I would be very empathetic that our schools, our parishes, exist to teach a Catholic view of marriage. Any words or actions which work contrary to that would be viewed very seriously," he said.
"Our teachers, our parish employees are expected to totally uphold the Catholic faith and what we believe about marriage. People have to see in words and in example that our teaching or marriage in underlined."
He said like all other employers, the Catholic Church should be able to ensure its values were kept by those who chose to work for the organisation.
In this he was supported by Archbishop Timothy Costelloe, chair of the Bishops Commission for Catholic Education, who warned teachers against "undermining" their schools' values if same-sex marriage was legalised.
Parents who sent their children to a Catholic school wanted them educated within a Catholic context, of which marriage was a vital part, Archbishop Costelloe said.
The Anglican Church declined to comment directly on employees when contacted by Fairfax, but emphasised the importance of protecting religious freedom.
Under Australia's anti-discrimination laws, churches have exceptions allowing them to hire and fire on the basis of sexual orientation, marital status and other traits.
Father Frank Brennan, chief executive of Catholic Social Services Australia, this week defended the ability for church schools to refuse employment to a same-sex attracted person, and for aged care facilities to reject a married gay couple.
But Catholic Health Australia, the country's largest non-government, non-profit health group, distanced itself from those threats.
Chief executive Suzanne Greenwood said she would not expect medical staff to observe the church's teachings so strictly, but thought it might be different for teachers.
A 2015 paper by the Australian Catholic Council for Employment Relations found that more than 180,000 Australians worked for the Catholic church - about 2 percent of the workforce.