Labor has “no plans” to change religious exemptions in discrimination law that allow religious schools to fire teachers based on their sexuality, Tanya Plibersek has said.

While the Labor deputy leader did not rule out a future Labor government considering such changes, her comments on Sunday indicate the opposition will defend the status quo during the Ruddock religious freedom review.

On Sunday the National Catholic Education Commission (NCEC) released its pre-budget submission, which reiterated the importance of religious freedom to be reflected in schools’ teaching, employment and enrolment practices.

It noted the passage of same-sex marriage legislation and said religious freedom had to be upheld so Catholic schools could “teach and foster a school environment that reflects the mission and identity of the Catholic church”.

Religious schools are currently exempt from federal discrimination law in relation to employment and provision of education in accordance with their beliefs. Similar exemptions exist in state discrimination laws.

Asked about the call for religious schools’ ability to retain a power to sack gay teachers Plibersek told reporters in Sydney “we’re not proposing to change any of the current exemptions for Catholic schools”.

“What I would say is that most Catholic schools are very thoughtful about keeping the very best staff,” she said. “I don’t expect to see a spate of people sacked because of their sexuality.”

In November a Baptist school in Rockingham, Western Australia, sacked a relief teacher who revealed his sexuality in a Facebook post.

During the marriage law postal survey campaign the Catholic church threatened to sack gay teachers, nurses and other staff if they engaged in civil same-sex weddings in breach of church doctrine.

Plibersek said Labor had “no plans to change anti discrimination law at schools at the moment, we think the balance is about right”.

In November during the marriage equality debate the Turnbull government asked former attorney general, Philip Ruddock, to head a snap review of religious freedom in Australia.

The religious freedom review is accepting initial submissions until 31 January and will report back by 31 March.

On Wednesday Ruddock said the expert panel, which will meet for the first time next Wednesday, had made no decision on whether or not to keep submissions to it secret.

Before the 2016 election the Greens promised to remove religious exemptions to discrimination law for religious schools.

In its 2018 budget submission the NCEC asks for a further $1.1bn to transition to the Gonski 2.0 funding package over 10 years rather than six.

According to the NCEC the schools reform allows overfunded independent schools a 10-year transition period before they reach their allocation of federal funding.

Catholic systemic schools reach their share in six years, resulting in a “$1.1bn financial penalty” relative to independent schools, the NCEC argues.

The education minister, Simon Birmingham, has rejected what he calls a “scare campaign” and pointed to the fact Catholic schools will get $300m next year and $3.5bn over the decade.

Plibersek recommitted Labor to “restore every dollar” cut by the federal government from projected funding growth, or $17bn over 10 years.