Belfast City Council is investigating how a man was able to deliver a hate speech at City Hall, it has emerged.
The preacher provoked fury by branding abortion "murder" and homosexuality "sin" in God's eyes, using the steps in front of the iconic building in the city centre as a podium.
The PSNI is also probing the matter.
Feminist activist Kellie Turtle, who initially raised the issue on Twitter, told the Belfast Telegraph that her main concern was that he was allowed to voice his views from the heart of local government.
She also called on Belfast council to "explain, apologise and make sure this never happens again".
"There is something seriously wrong when hard working social justice organisations have to jump through endless logistical hoops to hold rallies on the cobblestones outside City Hall, but this clown can just walk up to the steps and preach hate," she said.
"As a person who had an abortion, it is totally unacceptable to me that somebody can stand on the steps of my City Hall, the most important institution of governance in my city, and call me a murderer.
"And when he gets to do that it does seem like an endorsement - or at the very least negligence."
A video of the individual appears on the Facebook page of an organisation called Hope on the Streets Belfast.
In it, the preacher says: "This is a government here that is following the spirit of the antiChrist. It's making laws that go against the law of God. Heaven is coming down one day and all the governments of this world are going to go to hell."
The organisation has been approached by the Belfast Telegraph for comment.
Green Party councillor Anthony Flynn condemned the "hate speech" and said that a repeat performance must be prevented.
"Belfast must be a city for all, and our City Hall should be a safe space and a visible symbol of the transition that our people have made towards peace, tolerance and progress," he said.
"The incursion onto the grounds of City Hall and the hate speech that was delivered violated so many of our citizens.
"There are two issues to deal with here. Firstly, the grounds of City Hall are closed because of the pandemic, and I've contacted council officers to ensure that security is maintained, and this stunt isn't repeated. Secondly, the right to free speech is no defence for hate speech. The sentiment expressed in the grounds of City Hall has the potential to cause deep hurt and harm.
"Hate preachers have blighted our city centre for some time now and violated the right of people to enjoy the public space.
"This incident represents an escalation of the campaign to use our civic space to abuse others. This is a nasty, tiny but very noisy element of our society. There is a security response needed from Belfast City Council. But, there is a separate and wider community response which involves respecting each other, showing kindness and treating people with dignity and respect."
A council spokesperson said: "City Hall grounds remain open for public use, but permission is required to stage any form of event within the site.
"Using the grounds without permission in this way is a breach of current park bye-laws, and council is currently investigating this incident."
A PSNI spokesperson said police have received a complaint in relation to a man preaching outside the City Hall. He added: "The matter has been reported as a hate incident and enquiries are currently ongoing."