A Christchurch grandmother who admitted a $250,000 benefit swindle has been jailed for nearly three years today by a judge who called those who believe benefit fraud is not a serious crime as being "misconceived and misguided".

Jasmine Kasiana Teowai Hudson, 62, ripped off the welfare system repeatedly between 2000 and 2015.

Over that 15-year period, Hudson received an invalid's benefit, supported living benefit, reduced Housing New Zealand rent, special needs grants, and temporary additional support while falsely claiming she was not living with a partner.

At Christchurch District Court today, Judge Tony Couch said he had no option but to jail her.

"There is a view apparently held by some people that benefit fraud is somehow less serious than other forms of dishonesty but that is a totally misconceived and misguided point of view, dismissed by the higher courts," Judge Couch said.

Benefit theft stole from the whole of society and involved a breach of trust, with grants being given to people who needed help on the assumption they were being honest, he said.

Hudson earlier pleaded guilty to 19 charges of benefit fraud, amounting to $246,871.96.

Defence counsel Elizabeth Bulger said her offending stemmed from "need and not greed".

She had been in an off and on relationship and had initially got a benefit legally.

But when her circumstances changed, and kept changing, it was "obviously much easier" to keep getting the income than go on and off it, Bulger said.

The money was not spent on overseas holidays or furnishing her house, but rather running her household, bringing up children and meeting day-to-day needs, Bulger said.

She has been caring for a family member and two young grandchildren, the court heard.

Oranga Tamariki, Ministry for Vulnerable Children was aware of the court case and its potential consequences, Ministry lawyer Jennifer North said.

Judge Couch said he had considered her case seriously and while he had to take into account her personal situation, he had to make her accountable for the harm she has done.

He sentenced her to two years, seven months imprisonment.

Hudson, who has been on benefits since 1989, has a substantial criminal history with 22 convictions, including seven for dishonesty, and has been jailed twice before.