A former policy adviser to the New Zealand Law Commission, the 42-year-old has begun a High Court challenge.
Diagnosed with an untreatable brain tumour in 2011, Ms Seales has now been left paralysed on the left side of her body.
Medical reports reveal she is expected to die in the coming months, if not weeks.
Despite this, she is choosing to spend her last days challenging an interpretation of New Zealand’s Crimes Act that makes it illegal for doctor-assisted euthanasia.
In an affidavit read by Ms Seales lawyer to the court, she said the ability to have some control over the final stages of her life would give her great comfort and she described the relief as “extraordinary”.
“It’s one of the most significant things that could improve the quality of my life now,” she wrote. “I want a choice to say enough is enough.”
Ms Seales said she was scared of incontinence, choking and intense pain. She said she didn’t want to be in a drug-induced haze, where she would be unable to recognise her husband, or fall into unconsciousness and have her family watch her slowly die, unable to eat or drink.
Prior to her diagnosis, Ms Seales described herself as fiercely independent, a determined woman who did not want to lose her dignity or have her family endure her suffering.
At the hearing, held this week, an Australian palliative care expert argued that Ms Seales would continue to suffer despite palliative care and that she was at significant risk of a long period of bed rest before her death.
Something that, given her independent character, she would find hard to endure, the expert added.
“In the circumstances I consider palliative care will be unable to resolve Lecretia’s suffering,” he said.
Ms Seales GP also testified that she would be happy to assist her patient to end her life, if the court ruled that thsi would not be breaking the law.
Despite her medical team confirming she is not depressed, concerns were raised that Ms Seales could take her own life prematurely should she not be given the right-to-die, something she was considering.
The 42-year-old women argued that a total ban on doctor-assisted death would breach her rights under the country’s bill of rights.