A Hamilton man would make his stepchildren watch porn, smoke cannabis and indecently assault them over a period of at least a year.

The man, 34, who cannot be identified to protect the identity of the child victims, was yesterday jailed for four and a half years on two representative charges of indecent assault of the two girls, aged 12 and 14, and two representative charges of assaulting the girls, both over a period between September 21, 2009 and September 23, 2010.

The man would ask the girls to smoke cannabis, watch pornography and go into their bedrooms where he would unbutton their clothing and touch them.

The court heard the man's demands were constant.

The man would also hit and kick the girls on other occasions.

The man's counsel Richard Barnsdale said his client had pled guilty early to the assault charges while he pleaded to the indecent charges on the morning of the trial.

Mr Barnsdale said the degree of violence was unclear, so asked for any increase in sentence in that respect be "moderate".

Judge Merelina Burnett didn't accept the man's defence that he was "set up" by the mother, his former partner.

"The victim impact statements that are before the court can leave me in no doubt as to where the culpability lies. The victim impact statements make profound reading and clearly the two victims and of course their mother will have to sustain the anguish of having placed her two young daughters within the reach of your  predatory (reach)," Judge Burnett said.

She was also unimpressed that he continued to deny the offending, and concerned that he was at a moderate to high risk of committing sexual and violent crimes again.

"You simply predated on them because they were available and vulnerable."

The man had an "extensive list of previous convictions", some for sexual-related crimes.

Aggravating the sentencing was instances where the man would hit the girls if they didn't comply with his demands.

Judge Burnett handed down a prison sentence of four years and four months, but added another six weeks, for remitting his $14,317.89 in fines.

- © Fairfax NZ News