A man who raped his adult daughter has been sentenced to nine and a half-years imprisonment, at the Nuku'alofa Supreme Court.

Hon Mr Justice Cooper sentenced him on July 30, after a trial when he found him guilty on three counts of rape and two for serious indecent assault, committed on Tongatapu.

He also made an order under Section 119 that no detail could be reported that tends to identify the complainant in this case.

The judge increased the sentence to nine and a half-years imprisonement to reflect the severity of this rape case, which included a violent attack on the complainant.

However, due to him having no previous convictions, the final 12-months was suspended for two-years on conditions.

During that time, he must report to a probation officer and complete a life skills course and not commit any offences punishable by imprisonment, he said.

"If any of those conditions are breached then he will be sent back to prison to complete the unspent portion of his sentence."