The petition has had no effect, says the cinema
Ninety people in Wellington have signed a petition protesting at the film for what they call its "occult connections" and presented it to the manager of the town's only cinema.
"I did a lot of research and realised it was all about the occult and became very concerned," Ms Sparkes told BBC News Online.
'Good business'
"I decided to set up a petition, even though it was too late to stop the film being shown in our town."
The petition calls on the Wellesley cinema to stop showing the film - but the cinema says that it has done "extremely good business" with the Potter film, which has been a blockbuster hit worldwide.
Stewart Cusack, leaseholder of the Wellesley cinema, described the petition as "a ridiculous waste of time".
"You shouldn't try to impose your beliefs on other people," Mr Cusack told BBC News Online.
"Earlier this year we had the Hannibal film on - why didn't they complain about that?"
Mr Cusack added that the petition had had no discernible effect on attendance.
Fantasy
"We've done extremely good business - we're extremely pleased and the film's run has been extended from three to four weeks," he said.
But Ms Sparkes dismisses suggestions that the works of JK Rowling are a harmless fantasy.
"They are definitely not harmless - it is showing people how to do witchcraft," she said.
"We will continue to try to get people more aware of the dangers of the occult."
Community
The town's Baptist minister, the Reverend Sam Griffiths, believes the row has been overplayed.
"This isn't a big issue in our community," he told BBC News Online.
"Though I sympathise with Ms Sparkes' views, I think the film is quite good and I'm saying something different.
"I'm saying, 'Hey, we need to engage with this' and not just ban it - saying no to this is not helping us put the Christian message across."
Distributors Warner Bros declined to comment.