The State will present arguments to the Supreme Court today why the blanket ban on assisted suicide should be upheld.
59-year-old Marie Fleming, who is terminally ill with multiple sclerosis, claims she has a right to die with dignity at a time of her choosing.
Mrs Fleming's lawyers have been outlining why they believe the High Court was wrong to rule against any relaxation of the ban on assisted suicide.
They say the law could be modified to accommodate a small group of people who like her are mentally competent, terminally ill and suffering enormous pain.
They argue this can be done without increasing the risk of involuntary deaths.
The State will open its case today - the High Court accepted its evidence that one exception may be the start of a slippery slope that would end in a paradigm shift in behaviour.
Marie Fleming's lawyers say changing the law would do no more than put her on an equal footing with an able-bodied person with the power to end their own life without assistance.