A woman has filed a lawsuit against a Florida megachurch after it reportedly did not pay her the promised hush money to keep her alleged affair with a pastor a secret.

Church member Arlene Miranda filed the suit against Orlando Baptist Church based in Orange County, saying the church failed to pay the agreed $3,000 so she would keep quiet about her alleged affair with Pastor David Janney, 61, married, and the church's president.

"They threatened me. If I didn't sign it, they threatened me," Miranda told WFTV.

Miranda denied she filed the lawsuit for the money, saying "I committed a sin. The Holy Spirit really, really convicted me and I wanted to come clean."

Her lawsuit is being shouldered by businessman Craig Mateer, who sued Janney's charity in 2012, accusing it of misusing funds. The case was eventually settled out of court.

Mateer allegedly gave $117,000 to Janney's World Hope, but based on investigation, the money appeared to have enriched Janney, according to the Orlando Sentinel and Raw Story.

In her lawsuit, Miranda said she's been a member of the church since 2008. Last September, she claimed that Janney "started making sexual advances towards" her.

"David Janney texted Plaintiff about his sexual fantasies about her," the lawsuit said, adding that on the following Labor Day weekend, they had an affair at the World Hope office.

After the affair, Janney continued to text her about the incident and its effect on him.

"You're beautiful, you're very sexy, your body is amazing and you're very passionate," he allegedly told her.

"I wish we had a better place and a better time for today. You're more than I fantasised. Be proud of yourself. [A]nd now please give me a few days to work through my mind my heart and talk to my Lord. More than anything I want to be the man of God and your pastor," Janney allegedly wrote her.

But when Janney learned that Miranda had disclosed the affair to Pastor Don Norman, "he sent her threatening text messages regarding her and her children, and demanded she keep quiet about the affair," the lawsuit read.

On Dec. 2, Janney and other church officers presented Miranda with a non-disclosure agreement that promised to pay her $375 a week starting Dec. 4.

"In return, Plaintiff would not disparage David Janney, OBC, Inc., or otherwise disclose her affair with David Janney," the lawsuit read.

Miranda signed the agreement. She later said she didn't receive any payment up to the time she filed the lawsuit.

Because of the scandal, Janney resigned from the church.

"Pastor Dave Janney resigned as the Senior Pastor effective Sunday, February 7, 2016, not because the allegations against him are true, but because he felt his resignation was in the best interest of the Church," the church said in a statement.

It added, "Orlando Baptist Church is saddened by the resignation of Pastor Dave Janney. He leaves with our love and support. As a church we desire to extend grace and love to all, in all that we do. The church will be forming a pulpit committee that will lead in the process of selecting a new pastor. Ultimately our church members will be able to ask questions of, and vote for, any new pastor."