A Christian pastor is suing a United States health department for "religious discrimination" after he was fired because of statements he made in sermons.

LGBT groups protested when Dr Eric Walsh, from Pasadena, who had been an advisor on HIV/Aids to President Barack Obama, was offered a job in 2014 running a district of the health department in Georgia. They were concerned that he was opposed to homosexuality.

The offer was then rescinded. Dr Walsh was also placed on administrative leave from his job as Pasadena public health director, so that officials could look into his sermons in which he described homosexuality as sinful and also criticised evolution, Islam and Catholicism, according to the Daily Caller. He then resigned from that job.

In a statement at the time, a Georgia health department spokesman said the background checks led to the job offer being retracted.

A Facebook page has been set up to support Dr Walsh.

The lawsuit has been filed by First Liberty Institute which wrote: "In May 2014, the State of Georgia's Department of Public Health hired Dr Walsh as a District Health Director. But soon after Dr Walsh accepted the offer, state officials asked him to submit recordings of his sermons for their review. After inspecting his sermons, they fired him. First Liberty Institute filed a lawsuit against the State of Georgia on behalf of Dr Walsh because no one should be fired from his job for something he said in a sermon."

Liberty cited an email which showed health staff had been assigned to listen to Dr Walsh's sermons on YouTube. Liberty also has a voicemail where public officials laughing and using words like "you're out" without realising they wer being recorded.

Dr Walsh holds both a medical degree and a doctorate in public health. He is also a lay pastor in the Seventh Day Adventist Church.

Dr Walsh said: "My mom was a single mother and what got us through was our faith. What I learned at church taught me the value of getting an education and led me to want to serve those in need. That's why I became a doctor and I've held onto those beliefs ever since."

He added: "I couldn't believe they fired me because of things I talked about in my sermons. It was devastating. I have been unable to get a job in public health since then. By reviewing my sermons and firing me because of my religious beliefs, the State of Georgia destroyed my career in public service."

He also wrote: "I am a devout member of the Seventh Day Adventist Church, and, as a part of my sincerely-held religious beliefs, I believe in expressing my faith….My faith is important to me; I regularly speak about my faith at churches and religious conferences."

Liberty filed a charge of discrimination in September 2014, charging Georgia public health department with religious discrimination and retaliation for firing Walsh over the content of his sermons. In February this year Walsh was given the right to sue, and First Liberty filed the suit this week.

Andrew Coffman, partner at Parks, Chesin & Walbert, who are working with Liberty, said: "No one should be fired for simply expressing his religious beliefs. In America, it is against the law to fire an employee for expressing his religious beliefs – especially when that expression takes place at church."

Jeremy Dys, Senior Counsel for First Liberty, said: "If the government is allowed to fire someone over what he said in his sermons, then they can come after any of us for our beliefs on anything. We must ensure every American has the right to talk about their faith at church without getting fired or being barred from public service."

Todd Starnes of Fox News wrote: "Bi-vocational pastors be warned – what you say from the pulpit on Sunday could get you fired from your public sector job on Monday."