A man who is now a marriage guidance counsellor threw his wife into a door frame, splitting her head open, then dragged her down the hall by the neck.

The attack on the woman was watched by her 6-year-old son, who grabbed his stepfather around the leg, yelling, "Leave my mummy alone."

The man was convicted this week on two charges of assaulting his ex-wife and was sentenced to six months' home detention - enabling him to keep working as a counsellor.

The trial, in the Manukau District Court, lasted three weeks.

The attack happened 15 years ago but the victim took years to build up the courage to face the man in court.

She had also grown frustrated at his rising profile in marriage guidance.

Judge Semi Epati granted the 50-year-old man name suppression, a decision which angered his victim.

The former wife, who cannot be identified because of the suppression order, told the Weekend Herald she felt let down by the court system.

"He is a marriage counsellor with two convictions for male-assaults-female and injuring with intent," she said.

"The public would be horrified to know that there is no way of finding out who this person is.

"He lives in a mansion and can keep counselling there. It's disgusting."

Judge Epati granted name suppression despite opposition from the Crown.

But he gave permission for the Crown to alert agencies such as the Family Court, police, Child, Youth and Family Services and the Counselling Association who refer clients to the man.

But the public will have no way of knowing the man's identity.

The case comes a week after the Minister of Justice, Simon Power, announced stricter criteria for the granting of name suppression. The changes do not come into force until the end of the year.

Court documents show the attack happened in the hallway of the home the couple shared in Auckland in September 1995.

After an argument about custody issues over his children from a previous marriage, the man grabbed his wife by the neck and slammed her head against the door jamb, making her head bleed, then dragged her.

Her injuries included bruising to her shoulders, neck and chest as well as a laceration and bruising to the left side of her head.

The woman stayed at a friend's safe house before ending the 16-month marriage and leaving the country with her son.

When police spoke to her ex-husband, he said: "[She] has been making these allegations for years. Both CYFS and the Family Court have been involved and found nothing."

The woman was also upset that Judge Epati did not let her read her victim impact statement to the court.

The man and his current wife - his third - own a marriage-counselling business in the North Island.

They are Christians and qualified counsellors who offer 90-minute counselling sessions, which start at $120.