An elderly victim of a scam reads through the list of withdrawls against her card.

Two sisters have been jailed for their part in a crime ring that scammed elderly and vulnerable victims out of $240,000.

Christchurch District Court Judge Raoul Neave described the offending as "utterly despicable behaviour".

But he was impressed that the sisters, Leanna Korau, 27, also known as Wylie, and Tayla-Dane Korau, 26, had fronted up to the families of the elderly victims at a restorative justice meeting.

The judge said he received an "extremely encouraging" report from the meeting, where the women came face to face with the effects of their offending for the first time.

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Meeting the victims' families would not have been easy, he said.

Both women are mothers and should realise the time had come to make the choice to put their children first, the judge said.

He noted Tayla-Dane Korau's eldest son did not want anything to do with her as a result of her repeatedly going back to prison. "I can imagine few things as devastating for a mother as that."

Crown prosecutor Pip Currie referred to the women's callousness in targeting elderly and vulnerable victims.

The sisters' mother spoke in court, telling the judge their offending had arisen through relationships with violent men.

Police said the crime ring contacted elderly women by phone and told them there was a problem with their bank card payments and their power could be cut off.

One of the women would then arrive with a "replacement" bank card, which was actually a Prezzy card, and would leave with the victim's bank card and PIN number. Their account would then be cleaned out.

Police said the group caused losses totalling $240,000, but Leanna Korau received only $3000 and Tayla-Dane up to $10,000.

For Leanna, defence counsel Margaret Sewell said her client had been in the grip of a methamphetamine habit, and had been easily led into the offending.

For Tayla-Dane, April Kelland said the restorative justice meeting had been a revelation. It indicated a young woman who was prepared to think about what she was doing.

Judge Neave jailed them both for 19 months, and ordered both to pay $3000 as emotional harm reparations.

He reduced their sentences for their participation in restorative justice meetings, their commitment to pay reparations, their genuine desire to change, and their guilty pleas.