A woman who gassed her children to death in the family car has lost an appeal against her conviction for murder.
The 43-year-old woman, who cannot be identified, was found guilty after a trial in the Supreme Court in Brisbane earlier this year of murdering her six-year-old son and 10-year-old daughter at their home at Sandstone Point, near Bribie Island.
She was also found guilty of the attempted murder of her 16-year-old son, and was sentenced to life in jail.
During the trial, the Brisbane court was told the mother decided to kill herself and the children as an act of revenge towards her ex-husband.
She had been angry, the court was told, after being issued with a Family Court order stating they would spend Christmas Day with their dad.
The mother gave the children crushed sleeping tablets before putting them in the back seat of the car, attaching a garden hose to the exhaust, and switching on the ignition.
The bodies of the children, who died from carbon monoxide poisoning, were found on November 22, 2002.
The woman took her case to the Court of Appeal in Brisbane in November, arguing her conviction was unsound because she was suffering from diminished responsibility at the time.
Her lawyer, Michael Byrne QC, also argued that information given to the jury about how one of the psychiatrists came to be involved in the case could have been prejudicial.
He said the correct verdict should have been one of manslaughter, which should carry with it a sentence of between eight and 12 years' jail.
However the crown argued the evidence about the woman's state of mind at the time supported a conviction for murder.
In a written judgment handed down on Thursday, the Court of Appeal unanimously dismissed the appeal.
In his reasons Justice Hugh Fraser said the evidence about the psychiatrist could not have contributed to a miscarriage of justice.
Justice Fraser also found the verdict was sound because the woman had not proved she was unable to control her actions.\