A coalition of community groups wants a vote on laws to boost discrimination protections for religious Australians delayed so any unintended consequences can be scrutinised.
Faith, medical, business and LGBTQI+ groups also want federal parliament's joint human rights committee to have more time to consider the bill.
Attorney-General Michaelia Cash has asked the committee to report back by February 4.
The bill is listed for debate in the House of Representatives on Tuesday.
It would protect people expressing their religious beliefs as long as this wasn't done maliciously or in ways that vilified, threatened or intimidated others.
Religious schools could also preference hiring people of the same faith, overriding legislation in train in Victoria.
Pitt Street Uniting Church's Reverend Jo Inkpin said voting on a bill before its consequences could be fully understood was irresponsible and unreasonable.
"This is a complicated piece of legislation that may have unintended consequences, winding back hard-fought protections for vulnerable communities," she said.
The Royal Australian College of General Practitioners was concerned the laws would affect access to health services for women and vulnerable groups.
"The proposed law could compound negative community attitudes toward those most vulnerable including minority groups and the LGBTQI+ community, as well as those in rural areas with fewer health services available," president Karen Price said.
Among those to voice concerns was homewares and furniture retailer Temple and Webster boss and Equality Australia board member Mark Coulter.
"This legislation may expose companies to reputational, financial and potentially legal risks and complicate enforcement of organisational codes of conduct," he said.
Australian Associated Press