Counselling services run by pro-life groups have been put on notice by Queensland's Health Minister Steven Miles, who claims they are misleading women.
The minister has written to the federal health ombudsman, claiming some pro-life organisations give women incorrect information and do not transparently declare their background.
"In some of the recordings I've heard they tell women they risk getting breast cancer from an abortion, which has been proven to be incorrect," Mr Miles said.
"They tell women that many women never recover from having an abortion, and they just generally encourage them not to exercise that option."
Mr Miles said the organisations often used neutral-sounding names despite strongly advocating a pro-life stance.
Some of the organisations identified by the minister in his letter to the ombudsman include Priceless House, Rachel's Vineyard and Pregnancy Help Australia.
"Look, it's no secret that Children By Choice offer a counselling service, but they're honest about it; (these organisations) use front telephone numbers and front names to be dishonest with women."
It comes as around a thousand people braved cold and rainy conditions in Brisbane to rally for abortion to be decriminalised on Sunday, ahead of the legislation being debated in parliament this week.
Mr Miles spokes at the rally, as did Federal Greens Senator Larissa Waters, former federal LNP Senator Sue Boyce, and Deputy Premier Jackie Trad.
The laws would take abortion out of the criminal code and make it a health issue, allowing women to terminate pregnancies up to 22 weeks' gestation.
Both the Labor government and the LNP opposition have granted their MPs a conscience vote on the issue, meaning at least a few LNP members would need to vote for the laws to ensure they were passed.
Ms Trad said she believed they would get the numbers to pass the legislation, but continue to speak to MPs until the vote.
"There have been conversations happening constantly over the course of the last two months," Ms Trad said.
"I think it's fair to say there is strong support for these laws that were independently drafted by the Queensland Law Reform Commission."
All the speakers urged those gathered to find out which way their local MP would be voting on the issue and urge them to vote to pass the legislation.
Under the changes, abortion would be allowed after 22 weeks with the approval of two separate doctors.
They would also enforce safe zones around clinics and medical facilities offering the procedure to stop staff and patients being harassed by anti-abortion activists.