The victim of a paedophile pastor has accused the man’s son, Hillsong Church founder Brian Houston, of not doing enough to expose his father’s crimes.

Brett Sengstock waived his anonymity as he told Channel Nine’s 60 Minutes program on Sunday night he was sexually abused by Frank Houston, the influential leader of the Pentecostal denomination Assemblies of God in the 1960s and 70s.

Sengstock had previously testified before the royal commission into child sexual abuse in 2013, under the pseudonym AHA.

But he told 60 Minutes he wanted to publicly ask Houston’s son Brian why he did not report his father to the police, despite knowing of his abuse since 1999.

Frank Houston, who died in 2004, was the head of Assemblies of God in New Zealand until 1971. Brian was the head of the Australian branch from 1997 to 2009, and founded Hillsong in 1983.

Frank was accused of sexually abusing nine boys, including Sengstock, and in 2015 the royal commission found Brian Houston had failed to report his father’s abuse to police.

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

He told the commission his father “never, ever preached anywhere” again, but another former pastor, Barbara Taylor, gave evidence that Frank was seen preaching in Canberra the following month. He was eventually allowed to resign with a retirement package.

On Sunday, Sengstock said it was a clear conflict of interest for Brian Houston to have been the head of Assemblies of God while the church investigated his father.

He alleged that Frank Houston paid him $12,000 and asked for forgiveness, but the church offered no counselling or apology for the abuse he suffered. “It is like it has been brushed under the carpet,” he said.

Sengstock said he was routinely abused by Frank Houston between the ages of seven and 12. Frank frequently stayed at the boy’s family home when he visited Sydney.

Sengstock, who has terminal cancer, has also sued the church for compensation but was unable to prove that Assemblies of God was responsible for the abuse he suffered.

On 23 October, New South Wales Greens MP David Shoebridge used parliamentary privilege to say that Brian Houston had “failed the victims” of his father, and argued there was “a strong basis” for prosecution under section 316 of the Crimes Act, for failure to disclose a serious indictable offence.

“[Sengstock] has contacted my office for help,” he said in parliament. “He is suffering from a life-threatening illness and is concerned justice will not be served in his lifetime.”

On Monday, NSW police said Brian Houston was “currently being investigated by officers attached to the Hills police area command”, but provided no further information.

In a statement, the Hillsong Church said nothing was brushed under the carpet, as Sengstock alleged.

“While Pastor Brian is incredibly grieved on behalf of the victim, and acknowledges the inexcusable crimes committed against him, it is misleading that the report failed to mention the many who knew about this issue before it came to his attention.

“Pastor Brian was the one who actually took action when he learned of it as evidenced to by the transcripts of the royal commission … From the day Frank Houston was confronted by Pastor Brian, he never preached again.

The response also referred to a 2015 statement from the church, in response to the royal commission’s findings that Brian had acted “with the best intentions towards the victim”.

“It should be emphasised that Pastor Brian is not a perpetrator of abuse, has never been accused of abuse, and took immediate action to expose and stop a child abuser,” it said. “The abuse committed by the late Frank Houston, the father of our senior pastor Brian Houston, occurred many years before Hillsong church existed.”

A 2014 statement from Brian Houston also denied he had interfered in the investigation into his father.

“There was no delay in action – from the moment we knew and he confessed, his ministry stopped. We referred the matter to the national executive of the Assembly of God. The investigation and subsequent actions were then handled by the AOG without my interference.”