A Marton woman was today jailed for five years and nine months after killing her 3-year-old granddaughter, known as Cherish.

"Count yourself lucky," Justice Warwick Gendall told 57-year-old Joanne Jasmine Tahuri as he sentenced her for the manslaughter of her three-year-old grand-daughter in the High Court at Wanganui today.

He made the remark after observing that Cherishsiliala Tahuri-Wright, known as Cherish, died in Wellington Hospital on February 19 2009 after being struck by Tahuri two days earlier - just two months after the law was changed requiring tougher, deterrent sentences for such violence.

"People must learn to keep their hands to themselves," he said.

"They must understand that violence will be met with stern penalties."

Before taking into account any mitigating circumstances surrounding what he called "this tragic case," he considered a sentence of seven and-a-half years would be appropriate.

However, this was not a case of long-running cruelty but one of someone who was too free with their hands when under stress.

He said Tahuri was not well equipped to care for children, in this case Cherish and her cousin.

And it did her no credit that she initially took refuge in silence and denial, trying to explain away the injuries to Cherish as being caused by her boisterous little cousin or sustained in accidental falls.

Recognition must be given, however, to the decision by Tahuri, who originally pleaded not guilty to murder, to plead guilty to manslaughter two weeks into what otherwise would have been a four-week trial. He also took into account her dysfunctional upbringing and emotional and intellectual difficulties.

What happened, he said was as a result of her inability to control her anger and frustration. But it was inexcusable.

"You did your best for Cherish but you were not able to supply her with what she required."

Lance Rowe, for the Crown, asked that Tahuri, who had held out until the last moment casting suspicion on others, should be jailed for not less than six years and Peter Brosnahan, for the defence, suggested four or five years would be more appropriate.

He said she was a woman poorly equipped to deal with life, was herself the victim of shocking abuse and totally incapable of caring for the children.

The grey-haired Tahuri wept alone in the dock when the sentence was delivered.

There was no sign of her partner, or her family in the court.