A couple with 11 children between them have been sent to jail for assaulting and robbing an associate whom they believed had caused the state to remove the women's children.

Samuel Duncan Davis, 37, and Mihi Aniawhina Torbett, 28, were sentenced together in Timaru District Court yesterday on three charges - demanding with intent to steal, assault with intent to injure and robbery.

Judge Joanna Maze said the victim had thought he was a friend of Torbett and Davis. The couple had asked him to babysit Torbett's children for a weekend but two days later, after they returned, Child, Youth and Family removed the children.

Six days later, on June 20 last year, the couple encountered the victim and accused him of being responsible for the children being taken away.

"You verbally abused him and assaulted him and forced him to come back to her [Torbett's] address," Judge Maze said. "You told him he was going to get a hiding when he got to the address."

He was punched and kicked by both of them as they walked to the house and then dragged inside, where they continued to verbally abuse him and punch him about the head and body.

"You told him he could leave and then Davis hit him with force from behind and he fell to the ground and you [Davis] stomped on his head," the judge said.

The victim's jacket and shoes were taken and he was told he had to pay the couple his weekly benefit until the children were back in Torbett's care.

The victim was taken to hospital for treatment and refused to make a statement to police. The following week Davis encountered the victim again and told him he had to give him the benefit money, which he did. After this, the victim went to police.

Torbett, a mother of six, was sentenced to two years and five months' imprisonment, with Judge Maze noting she had convictions for assault in 2001, 2009 and 2012, as well as a conviction for aggravated burglary in 2006.

Davis, a father of five, was sentenced to three years and two months' jail.

His previous convictions included five assault charges and five assaults female charges between 1992 and last year.

- © Fairfax NZ News