​A man who regularly had sex with his adult transgender stepdaughter over 13 years has been jailed for a decade for offences a judge described as "abhorrent and unacceptable".

The victim was born a boy but underwent gender reassignment surgery as a young adult about the time her mother and the man married, and soon afterwards he began exerting sexual control over her.

The judge found the accused guilty of "psychological manipulation of the highest order". Credit:Ken Irwin

The County Court heard on Tuesday that when the offending began, the stepfather was aware of the psychological difficulties the woman faced at that stage of her life, and that he preyed on her vulnerability.

He did so, the court heard, by threatening to financially ruin her mother if the sex was reported, and telling the young woman her family hated her.