Christian Porter has sought to allay concerns that a federal religious discrimination bill could water down protections for LGBT people in state legislation.

The attorney general told Guardian Australia the bill “is not intended to displace state law nor will it import specific provisions of international law” after LGBT advocates warned that it could undermine state protections against vilification or discrimination on the grounds of sex or sexuality.

As Porter has begun a series of workshops with Coalition MPs to discuss the as yet unreleased bill and agreed to meet religious leaders such as the Sydney Catholic archbishop Anthony Fisher, advocates have demanded he meet with affected LGBT and women’s groups and guarantee the bill will not wind back state regimes.

That call was echoed by the Tasmanian Labor shadow attorney general, Ella Haddad, who has written to the entire federal Labor caucus asking for a commitment state laws “will not be adversely impacted” – to which federal Labor is yet to commit.

Concerns centre on laws in Tasmania, Queensland and the Australian Capital Territory, which prohibit vilification on the basis of sexuality and – unlike New South Wales – do not provide a specific exemption for religious speech. Those states also prevent religious schools from expelling students based on sexuality, while Tasmania and the ACT provide the same protection to teachers.

Equality Australia’s director of legal advocacy, Lee Carnie, has warned that inconsistency between state and federal laws could allow litigants complaining of indirect religious discrimination to side-step state regimes.

Equality Tasmania and Just Equal spokesman Rodney Croome said there was a “high risk” of state and territory laws being overridden – particularly if the Coalition accepts the demands from faith groups to add a right to religious freedom contained in article 18 of the International Covenant on Civil and Political Rights.

Porter’s comments not to “import specific provisions of international law” appear to rule this out, holding the line against Coalition conservatives calling for the remit of the bill to expand beyond making religion a protected attribute to granting a positive right to express religious beliefs.

Carnie welcomed the attorney’s claim the intention was not to override state regimes, while Croome warned the “devil will be in the detail”.

“We would add that we hope the religious discrimination bill would provide consistent protections for best practice anti-discrimination laws … [to] ensure people living in states with strong protections – such as Tasmania – would have consistent coverage against discrimination on all grounds,” Carnie said.

On 30 June, Haddad wrote to her federal Labor counterparts urging them “not to allow the balance our law strikes to be undermined by any federal legislation”.

“The rights of vulnerable people should guide Labor’s policy-making when it comes to discrimination law,” she said. “Before Labor makes any decision regarding religious discrimination or freedom legislation the Morrison government puts forward, it conducts a sweep of state and territory anti-discrimination statutes to ensure they will not be adversely impacted.”

Croome said LGBT people in Tasmania and around Australia “want commitments from Scott Morrison and Anthony Albanese that they will not support any new law that weakens existing discrimination protections at a state and territory level”.

The acting shadow attorney general, Brendan O’Connor, said that Labor “believes in an inclusive society” but stopped short of giving a commitment that LGBT people in states with more favourable regimes will not be worse off.

“We will speak up for everyone’s rights and freedoms,” he said. “The debate should never be about pitting one group of Australians against another – it should be about moving towards a more accepting and respectful society for all Australians.”

The ACT attorney general, Gordon Ramsay, told Guardian Australia he would not support “any attempts to use changes to the anti-discrimination framework to reverse the progress made towards a more equal and inclusive society achieved [by marriage equality]”.

“The Australian public’s demand for equality and protections against discrimination for our LGBTIQ community has been made clear.”

Ramsay said the federal government should pursue a “national human rights framework that understands the necessary balancing between competing rights and responsibilities rather than a piecemeal effort appease their base”.