What could possibly go wrong?

Australia is about to find out when Newcastle man Steve Smith - the last person to give evidence at the Royal Commission into Institutional Responses to Child Sexual Abuse in 2017 - tells it like it is as the only agnostic in the SBS series, Christians Like Us, from April 3.

"It was one of the most disturbing weeks I think I've had in my life, which is a pretty big call," said Mr Smith, 58, who was raised Anglican, sexually abused by Newcastle Anglican priest George Parker as a young boy, and whose powerful testimony to the royal commission rocked both church and state.

In 2018 Mr Smith wrote to NSW Attorney-General Mark Speakman seeking an apology from the State of NSW after what he calls an ambush - the day in 2001 he walked into a Newcastle courtroom to give evidence against Parker, only to be blindsided by a judge's attack against him, in a trial where three key players had undisclosed associations with the church.

Mr Smith's powerful evidence to the royal commission contributed to serious findings against a number of senior Newcastle Anglican diocese members, the resignation of Archbishop Roger Herft, and criticism of lawyers who failed to disclose their diocese positions while representing Parker.

Mr Smith initially agreed to live and be filmed for a week in a house with nine Christians out of curiosity, but said it was also linked to his need to understand the place of religion in his life after five confronting royal commission years exposed grave institutional failings across many churches.

"I was raised Anglican. I wanted to see what makes Christians tick today after the royal commission, and see if there is a place there for me. I found there wasn't," he said.

"The people in the house represent different versions of Christianity. There was an Anglican woman priest and a gay Baptist guy I got on well with. There was a Coptic Catholic, a Sydney Anglican, a Uniting Church member, a Mormon, a couple of evangelical guys and a progressive Catholic from a Sydney girls' school.

"I was a great mystery to them at first because when we were introducing ourselves and it came to me, I was asked 'Where do you worship?' and I said, 'I don't'." 

The two-part series will show confronting scenes when a gay Baptist discusses "Pray the gay away" conversion "therapy" attempts by his church, and attitudes towards abortion and gay marriage.

It will also show the responses after Mr Smith revealed the sexual abuse he experienced as a child, and the fresh traumas he experienced after repeatedly reporting the abuse to Newcastle Anglican church representatives and pursuing the allegations in court.

Mr Smith said he was shocked and disturbed by some of the responses to confronting issues raised through the week.

"There was a lot of quoting from the Bible, but there didn't seem to be a lot of Jesus Christ in what some of them were saying," he said.

After he revealed his abuse one house member approached him and said: "Jesus weeps for you".

"I just turned and walked away. It's drivel. Jesus can weep all he likes but the question someone like me asks is: 'Where was Jesus when all of this was happening'?

"The point of me talking about what happened to me was to make them aware how the church, a Christian church, treated people. I was surprised at how little some of them had engaged with the royal commission."  

SBS director of TV and online content, Marshall Heald, said the series explored what it means to be Christian in Australia in 2019.

"Christianity in Australia is on the decline. Making headlines around the world, it's a religion currently facing scandals and dividing public opinion. Christianity has suffered steadily declining numbers, as a whole generation of Australians grow up with 'no religion'," Mr Heald said.

"The 10 participants showcase a diverse range of views, and are each deeply passionate and opinionated about their faith.

"Through debate and discussion, the series invites Australians to engage with the complex elements of Christianity and the issues currently facing the faith."

Mr Heald said the two episodes on April 3 and 10 will show "shocking revelations, emotional outbursts and surprising insights as they tackle sexual abuse in the church, abortion, gay conversion therapy and women as priests".

Mr Smith, a father of three, with three granddaughters, said the week answered one question for him.  

"I went in there wondering if there was a place for me in a church, and left realising my place is with my family," he said.