A newspaper ad placed in the Belfast News Letter ahead of the city’s Pride event is being investigated by the Advertising Standards Authority.
The 540-word advert, taken out by the Free Presbyterian Church, described gay people as perverts and criticised the parade.
The ASA told PinkNews.co.uk that a decision about whether it breached the code will be made in the next few days.
It stated that the gay community “desire to be known for a perverted form of sexuality.” and says the church will not be “intimidated” into silence.
“The act of sodomy is a grave offence to every Bible believer who, in accepting the pure message of God’s precious word, express the mind of God by declaring it to be an abomination.”
The advert was printed in the News Letter on August 1st, the day before Belfast Pride.
“This parade is not a welcome addition to our city, neither is it a positive celebration of a profitable lifestyle flaunting a form of sexuality that generations of men and women have righteously resisted and by God’s grace will continue to resist,” it said.
The Free Presbyterian Church was founded 56 years ago by Ian Paisley Snr, former First Minister of Northern Ireland.
It mounts a yearly counter-protest against Belfast Pride.
Last year veteran politician Paisley resigned as leader of the Church after coming under pressure from its members over gay rights issues.
The fundamentalist Christian sect were outraged that Mr Paisley and other members of his Democratic Unionist Party (DUP) ignored their objections to government financial support for Pride marches, which they called a “celebration of sodomy.”
Thousands attended Saturday’s gay Pride event in Belfast where DUP MP Iris Robinson, who is the wife of the First Minister, was mocked.
She ‘appeared’ at the event in the guise of masks carried by Pride participants.
More than 4,000 people turned out despite poor weather conditions. Thousands more watched the parade.
A float titled the ‘Iris Mobile’ joined the procession along the Belfast streets with a giant papier-mâché image of Mrs Robinson.
She told a House of Commons committee: “There can be no viler act, apart from homosexuality and sodomy, than sexually abusing innocent children.
“There must be sufficient confidence that the community has the best possible protection against such perverts.”
She previously said that gays could be turned straight with psychiatric help.
PA MagLochlainn, president of the Northern Ireland Gay Rights Association, told The Observer that it was due to Mrs Robinson that so many people attended the march:
“She has done us a favour because it has forced a lot of people to face up to the fact that homophobia still exists in Northern Ireland.
“‘Look how many have turned up today. The numbers are up because people want to show solidarity. She has helped the cause.”