The 48-year-old man's guilty plea comprised 12 separate cases of indecent assault and sexual intercourse with a young person.

The man had previously faced child sex charges interstate, but had been acquitted.

IN OTHER NEWS:

Justice Robert Pearce ordered the man serve a non-parole period of six years.

"This case is too serious for a short non-parole period," Justice Pearce said.

"Your conduct was not only cruel and heartless, but demonstrated a complete lack of remorse."

Justice Pearce ordered that his name be recorded on the Community Protection Offender Reporting register for 15 years.

In a victim impact statement read to the court last week the complainant said the man had messed up her life.

"(He) ruined my childhood and now he is ruining my life because I can't make it go away," she said in a statement read to the court by prosecutor Alison Shand.

The court heard that the man sent nude photos of the girl and sexualised chat to her classmates without her knowledge causing embarrassment and resulting in her being shunned at school.

"She was so embarrassed and distressed that she did not want to return to school," Justice Pearce said.

However, the man suggested home schooling which he used as an opportunity to engage in more abuse.

When the girl obtained her mobile phone the man used it to step up control and abuse.

"You used to monitor her to summon her presence for sexual conduct and to have her take photographs of herself and send them to you," Justice Pearce said.

"You threatened adverse consequences for her and others if she did not comply.

"You also made video recordings of her."

Justice Pearce said the man had committed a grave breach of trust.

"You have expressed no remorse and you have pleaded guilty at a very late stage," he said.

He had groomed the girl and exercised a level of control over her.

Sign up for our newsletters here