But 76 per cent say they thought social media was a good platform to use to post about their beliefs.
David Giles, Web and Social Media Manager for the Salvation Army, is behind the research and told Premier's News Hour a few people were worried about a negative reaction to religious posts online.
He said: "If we dive into the figures a little bit more, it's only about 8% that felt that the negative reaction they were receiving from their posts was discouraging them.
"So I think there are some legitimate reasons that have been expressed by some people, perhaps they don't feel comfortable enough or confident enough to express it to others."
Mr Giles told Premier that social media was positive in providing an avenue for Christians with different opinions to talk.
"The benefit of social media - the clue's in the name - it's social," he said.
"It's not just pushing messages out, it's an opportunity to discuss and hone ideas and be challenged in the way that we present our faith."
He went on: "I know that there are LGBT [lesbian, gay, bisexual and transgender] groups that are using Facebook to discuss Christianity and to have fellowship with other believers, when perhaps they wouldn't be opened so freely into other churches."
Listen to Premier's Alex Williams speak to David Giles here: