Brian Houston is one of the world’s most powerful pastors.

With his wife Bobbie, he founded the Hillsong empire, which pulls 100,000 people around the world into mega-churches each weekend to sing, dance and speak in tongues.

Last year in Australia alone, the church raked in $80 million of tax-free revenue.

Mr Houston rubs shoulders with the rich and famous – from John Howard to Justin Bieber, he has friends in high places.

But he is also being investigated for failing to report his father’s sexual abuse – committed against a seven-year-old boy.

Mr Houston was reportedly knocked back from attending dinner at the White House after the Wall Street Journal claimed his good friend, Prime Minister Scott Morrison, asked if he could tag along.

For years, Mr Houston’s father Frank abused as many as nine boys across New Zealand and Australia, including Brett Sengstock who testified before the royal commission into child sexual abuse in 2014.

Mr Sengstock told The New Daily he was horrified when he heard that Mr Morrison reportedly wanted Mr Houston at the dinner.

“I think it’s a slap in the face to all sexual assault victims and survivors who attended the commission in 2014,” he said.

“He’s preaching we’ve got to have love. It’s invalid. It’s an absolute scam.”

In his maiden speech to Parliament in 2008, Mr Morrison thanked Mr Houston for his “great assistance”, describing him as a mentor.

In July, he stood with his wife Jenny beside the pastor as they led a 1000-strong congregation in prayer – calling for more love and less judgment.

But Mr Morrison’s friendship with the pastor is in the spotlight – as Mr Houston’s decision not to immediately report his father’s actions comes under scrutiny.

Who was Frank Houston?

Mr Houston’s father Frank was the influential leader of the Pentecostal denomination Assemblies of God in the 1960s and 70s.

He frequently stayed with Mr Sengstock’s family when they visited Sydney from New Zealand, occasionally Brian Houston would stay too. As boys they got along, often playing on the beach together.

But these visits were hell for Mr Sengstock, who was abused by Frank Houston repeatedly when he was between the ages of seven and 12.

On a nightly basis, Frank Houston would sneak into Mr Sengstock’s room and force himself on the boy.

“I would be asleep when he came in, and then I would wake up with him standing over me,” Mr Sengstock told the royal commission.

“I remember that when he was touching me inappropriately I would be petrified and would lay very still.”

After the allegations became public within the church during 1999, Brian Houston sacked his father from his role as pastor, but wrote to churches telling them not to make the allegations public, and did not inform police of the multiple allegations.

Around this time, Frank Houston met Mr Sengstock, allegedly offering him $10,000, saying: “I want your forgiveness for this. I don’t want to die and have to face God with this on my head.”

Mr Sengstock said he agreed and signed a dirty napkin. But when the money didn’t show up a few weeks later, he claims called Brian Houston to find out what was going on.

Over the phone, Mr Houston allegedly told him: “You know, it’s your fault all this happened. You tempted my father”.

“Brian got very angry after that. He slammed the phone down after saying words to the effect of ‘You’ll be getting your money’,” Mr Sengstock said.

He allegedly received a cheque for $10,000 two weeks later.

Brian Houston has denied he said the abuse had been Mr Sengstock’s fault.

Now almost 20 years later, as the investigation into Brian Houston’s reticence to report his father unfolds, Mr Sengstock said the fight for justice has almost destroyed him.

“Frank would have done me a favour [by] killing me at the age of seven. It’s been a train wreck ever since,” he said.

“I’ve just had to battle on as best I can. I’ve been ostracised by family and friends, and people in the church they want nothing to do with me. It’s like I have leprosy.”

Brian Houston declined to comment to The New Daily, but a Hillsong spokesperson pointed to a prior statement from 2015 that said: “Pastor Brian acted in the best way he felt at the time and took decisive and immediate action against his own father.”