Franklin Graham has accused Facebook of 'censoring free speech' after he was banned from the social media platform for 24 hours over a 2016 post.

Graham, who is the son of late evangelist Billy Graham, said that in the post removed by Facebook he had challenged allowing transgender people to use the bathroom of the gender they identify with. 

'Well, now we know.  Facebook has a secret rulebook for policing speech. I was banned from posting on Facebook last week for 24 hours,' he said.

'Why? Because of a post from back in 2016 about North Carolina's House Bill 2 (the bathroom bill). Facebook said the post went against their "community standards on hate speech." Facebook is trying to define truth.

'There was a character in a movie a few years back who said, "The truth is what I say it is!" That's what Facebook is trying to do.

'They're making the rules and changing the rules. Truth is truth. God made the rules and His Word is truth. Actually, Facebook is censoring free speech. The free exchange of ideas is part of our country's DNA.' 

Graham, who also heads up Samaritan's Purse, said Facebook later unblocked him and issued an apology in which it said it had 'made a mistake'. 

The post about transgender bathroom access was also restored. 

Graham responded by saying he accepted the apology. 

'I thank Facebook for their apology and I accept it. All truth is in the Lord Jesus Christ, who is "the Way, the Truth, and the Life." I would encourage all Christians—as well as Facebook—to stand on God's Word and His truth,' he said. 

Christians and conservatives have long accused Facebook of being biased towards their views. 

Facebook CEO Mark Zuckerberg was challenged on the accusations when he was brought before Congress for questioning in April. 

Specifically, he was asked about the treatment of Diamond and Silk, the Trump-supporting duo who were told by Facebook that their content was 'unsafe'.

Republican Rep Joe Barton of Texas asked Zuckerberg during the two-day hearing: 'Why is Facebook censoring conservative bloggers such as Diamond and Silk? Facebook called them 'unsafe' to the community. That is ludicrous. They hold conservative views. That isn't unsafe.'

Zuckerberg responded: 'Congressman, in that specific case, our team made an enforcement error and we have already gotten in touch with them to reverse it.'

Just before Christmas, Facebook was again accused of censorship after it blocked a festive image of Santa kneeling before baby Jesus. 

Facebook did not remove the post but obscured the image so that users had to click on an 'Uncover Photo' button in order to view it. 

The blurred image was accompanied by a warning from Facebook that 'this photo may show violent or graphic content'. 

'This photo was automatically covered so you can decide if you want to see it,' it added. 

In October, the makers of pro-life movie Gosnell said Facebook had blocked their advertisements.  The movie, starring Dean Cain, tells the story of Kermit Gosnell, the notorious late-term abortionist who was given life without parole for the murder of three babies born alive in his clinic. 

Producer Phelim McAleer said some supporters had reported trying unsuccessfully to 'boost' their Facebook posts about the movie.

McAleer blamed a liberal bias in Silicon Valley. 

'The Silicon establishment do not want this story told,' McAleer said.

'They [Facebook] simply state it's not been approved and to check their standards, but it does not give you a specific reason why this post could not be promoted at all to a wider audience.

'It's clear it is the pro-life audience that they don't want to encourage or provide content to. They really hate anyone who doesn't subscribe to the liberal world view.'