A court has heard the most senior Australian Anglican clergyman to be charged with child sexual abuse used his power and influence to dissuade his alleged victim from disclosing the abuse.

Key points: Former Newcastle Anglican Dean Graeme Russell Lawrence is facing trial on child sex charges

Former Newcastle Anglican Dean Graeme Russell Lawrence is facing trial on child sex charges The prosecutor told the court a 15-year-old boy was "silenced" by Mr Lawrence

The prosecutor told the court a 15-year-old boy was "silenced" by Mr Lawrence Mr Lawrence has pleaded not guilty to all charges

The former Dean of the Newcastle Anglican Diocese, Graeme Russell Lawrence, is standing trial charged with aggravated sexual assault and aggravated indecent assault.

The alleged offences upon a 15-year-old boy in the New South Wales Hunter Valley date back to 1991.

Mr Lawrence has pleaded not guilty to all the charges and has been on bail since being charged in December 2017.

Up to 28 Crown witnesses are due to give evidence over the coming weeks.

Crown says boy silenced by fear

Graeme Lawrence was a senior figure in the Newcastle Anglican Diocese for decades. ( Facebook )

The court heard the 15-year-old boy was sexually and indecently assaulted after a youth band performance at Newcastle's Christchurch Cathedral in 1991.

The Crown alleges the boy was taken into a room in the nearby deanery, where Mr Lawrence lived, and where there were pictures of naked boys on the wall.

Crown prosecutor Craig Leggat SC said the boy was nervous when he realised he was only person there.

He said the then Dean removed the boy's t-shirt and forced him to the ground before sexually and indecently assaulting him.

The court heard at the time the boy thought about telling his mother but decided not to.

"The evidence will be that he thought about telling his mum what the accused had done, but he didn't think she would believe him," Mr Leggat said.

The prosecutor said Mr Lawrence also encouraged the boy to keep quiet.

"The accused tried to talk to him afterwards when he was in groups, when he would ignore the accused," Mr Leggat said.

"However there was one occasion when the accused spoke to the boy and said, 'Don't bother telling anyone, you know who I am, no-one will believe you'."

Defence barrister Paul Winch said the accused was in a position to be presumed innocent.

"It is not for Mr Lawrence to prove anything, it is for the Crown to prove its case beyond reasonable doubt.

"In addition to his pleas of not guilty, Mr Lawrence's position is that there was no sexual conduct at all.

"On no occasion did he invite the boy to the deanery and they were never alone together at any time."