"[It] was based on a concern that you may not retain day-to-day care of your children if you and your husband were to separate or divorce," his ruling said.
At about 7.30pm on July 28, the woman, who was living in the central North Island, put her two eldest children in a bedroom, where she read a story to them and talked about an upcoming holiday.
The children fell asleep and she returned to the living room to watch a DVD with her youngest child.
It was at that time the woman decided to carry out the suicide plan, the judge said.
"You left your child watching the DVD. You removed a knife from the kitchen and went to the garage. You obtained a hose from a vacuum cleaner and cut it in two lengths.
"You then took deliberate steps to turn off the house alarm system, so that any carbon monoxide fumes would not activate the smoke alarms, and fitted pipes in a manner that would allow the carbon monoxide to enter the bedroom."
After doing so, the woman spread flowers throughout the house and wrote a suicide note before taking her youngest child into the room.
She then started up the car that was sitting in the garage and went back into the room with her children.
"Your intention was that the carbon monoxide would operate to poison all four of you within about 15 to 20 minutes," Justice Heath said.
While in the room, she had second thoughts and, after an initial panic, called an ambulance, telling the dispatcher that she had tried to kill her children.
"An ambulance transported you and your children to hospital immediately. By this time, your youngest child was unconscious," the judge said.
All of them survived.
At last week's hearing, Justice Heath accepted the case was not "typical" and, although the victims were children, there was no need for a sentence of imprisonment to be imposed.
"In rare cases, even for such a crime as attempted murder, a merciful sentence is required to take account of significant extenuating circumstances and diminished responsibility on the part of an offender.
"Indeed, it is much more desirable that a sentence be crafted to enable you to better manage the psychiatric disorder under which you labour. Society will not be at further risk provided you are treated properly."
Under the standard conditions of intensive supervision, the woman must report to a probation officer at least once a week for the first three months of the sentence and at least once a month during the rest, and thereafter as and when required to do so.
Special conditions may be imposed in relation to a "programme" where she would have to undergo any psychiatric or counselling programmes and attend any medical, psychological, social or such programme as directed by a probation officer.