South Australian independent federal MP Rebekha Sharkie is launching legal action against the Australian Christian Lobby (ACL) for copyright infringement.
Ms Sharkie said two flyers produced by the organisation used a photo owned exclusively by her without her permission.
In a letter sent to the organisation today, the Mayo MP has given the ACL until Monday to publicly apologise.
Ms Sharkie also said she believed it was inaccurate and unfair to see herself portrayed by the ACL as attacking Christianity or the church in the materials due to her position on the Religious Discrimination Bill.
"If the Australian Christian Lobby do not apologise and do not remedy what I feel is wrong, I will be seeking to take further action," Ms Sharkie told ABC News.
The brochure said that Ms Sharkie "voted against protecting people of faith from discrimination and voted to remove laws that protect the value of Christian schools".
In February, Ms Sharkie joined five Liberal MPs Labor and other independents to vote against the government and extend protections for transgender school students.
"As a Christian, I support protections against discrimination on the grounds of religion, but I will not idly allow this extremist organisation to use my likeness to denigrate the LGBTIQ+ community, people fleeing domestic violence, going through divorce or seeking IVF treatment, Ms Sharkie wrote on social media.
"The views of the far-right ACL are not shared by a long list of religious organisations, including the Uniting Church, Anglican Church, St Vincent de Paul Society and so on."
ACL spokeswoman Wendy Francis said the organisation had not received any correspondence from Ms Sharkie.
"The photo of Rebekha Sharkie used on the ACL flyer is publicly available online in many places, including on the ABC election website," Ms Francis said.
"ACL has not been provided with any evidence that Ms Sharkie owns the copyright, as distinct from her assertions.
"None of these claims change the integrity of the campaign and its message.
"Ms Sharkie does not want people in her electorate to know that she voted against the Religious Discrimination Bill and moved the amendment to remove protections for faith-based schools."
Similar brochures and advertising about MPs across Australia feature on the ACL's Facebook page.
Those targeted included Liberals Fiona Martin in Reid, Trent Zimmerman in North Sydney, Dave Sharma in Wentworth and Bridget Archer in Bass, along with independents Zali Steggall in Warringah and Helen Haines in Indi, and Labor MP Anne Aly.
Ms Sharkie's seat of Mayo covers the Adelaide Hills, the Fleurieu Peninsula and Kangaroo Island.
She holds it with a 5.1 per cent margin over the Liberal Party.
