A Presbyterian Minister from County Tyrone has described plans to burn a wooden structure called Temple in Londonderry as a pagan practice.
Thousands of people have been visiting the site in the Waterside area of Derry where the 70-foot carved tower has been built.
People have been leaving personal messages inside the structure.
Around 15,000 people are expected to watch the burning of the tower on Saturday.
The aim behind Temple was to bring together the artist at the centre of the USA's Burning Man Festival in Nevada, David Best, and the people of Derry, to offer an alternative perspective on bonfires.
'Son of God'
Rev Graeme Orr from Magheramason said he fears the burning could leave people open to the "influence of the occult and Satan".
"I have a deep love for the people in Derry," said Mr Orr.
"I didn't know an awful lot about the Temple but it is about worship, and the idea that flames would bring healing or restoration is not an idea found in the Bible.
"True healing is looking to the son of God. We should be thinking more about his death on the cross coming up to Easter.
"I do believe that there is a dangerous element involved in this. There is great community spirit in this yes, but as I researched it I got more worried.
"I looked into the Burning Man which is similar to this and a culture has developed that anything goes.
"The Burning Man is linked to orgies and things.
"My fear that is that we go down a similar route to this in the future.
"Dealing with loss is extremely difficult but the burning of the temple is contrary to what the Bible says.
"It's not the way to God."
The company organising the event, Artichoke, has declined to comment on Mr Orr's comments.
The artist David Best said the idea for the structure originally came to him after he lost a close friend.
Presbyterian Minister David Latimer said he disagreed with Mr Orr.
'Pain and loss'
"My initial scepticism was to do with its location. I didn't think it would be inclusive for all communities.
"I visited the site recently and it is totally clear that people from everywhere and all traditions are visiting.
"Their messages represent the pain and loss that people have went through. It's a great form of expression.
"I don't think this is pagan.
"I know of girls who have been up to leave a message at the Temple on behalf of their mother who lost to babies recently. That's what this about."