A 25-year-old British Columbia woman is challenging Canada鈥檚 new assisted-dying legislation, arguing that the law鈥檚 requirement that death be 鈥渞easonably foreseeable鈥 unfairly rules out patients with chronic and untreatable conditions.

Beth Lamb was diagnosed with spinal muscular atrophy in early childhood. She uses a wheelchair and relies on aides to help her with daily tasks, and she fears that, if her condition worsens, the nature of her progressive disease will disqualify her from an assisted death.

"My biggest fear is that if my condition suddenly gets much worse, which could happen any day, I will become trapped," the Chilliwack, B.C., woman said at a news conference on Monday.

"I feel a shadow looming over me. I know I could lose the ability to breathe well enough on my own and require a ventilator, which could affect my ability to speak."

According to the Liberal-backed legislation, doctors can only provide medical help if a patient鈥檚 death is reasonably foreseeable and if the patient鈥檚 condition is in an advanced state of irreversible decline.

Lawyer: Patients face 鈥榙ecades of suffering鈥

This requirement leaves out 鈥渁 huge category of people,鈥 including those with multiple sclerosis, Huntington鈥檚 disease, Parkinson鈥檚 disease and locked-in syndrome, according to a litigation expert from the law firm representing Lamb.

鈥淭hese are people for whom death may be very far away, but they may be faced with the prospect of decades of suffering,鈥 Grace Pastine, litigation director of the B.C. Civil Liberties Association, told CTV鈥檚 Power Play on Monday.

The B.C. Civil Liberties Association has been contacted by 鈥渕any people鈥 like Lamb over the past week with concerns about the new law, Pastine said. The association has called on other chronically ill patients to come forward and join the lawsuit.

鈥淎nd we think it鈥檚 just really shameful that people like Julia have to come forward yet again, tell their stories yet again, when there are so many other things they should be focusing on in their lives. Because the Supreme Court of Canada granted them the right (to an assisted death) only to have the federal government take it away,鈥 she said.

The Supreme Court of Canada struck down Canada鈥檚 ban on assisted death in 2015, and gave the federal government until June 6, 2016 to write a law. After plenty of back and forth between the House and Senate and a brief period of legal limbo, Bill C-14 received royal assent on June 17.

The constitutional challenge has been filed to the B.C. Supreme Court, and Pastine expects it will make its way up the justice system all the way to the Supreme Court of Canada.

鈥淲e鈥檙e just calling on the government to make this process as quick as possible. We would like to seek a speedy trial. We do not want sick and suffering Canadians to have to endure another incredibly long wait,鈥 she said.

Wilson-Raybould: Law is 鈥榯he right approach鈥

But Justice Minister Jody Wilson-Raybould said she is confident that the newly minted law is fair and constitutional.

"It represents the right approach for Canada at this important time in our country's history by striking the balance between personal autonomy for those seeking access, protection of the vulnerable, and respect for the conscience rights of health-care providers," Wilson-Raybould said.

Without access to an assisted death, patients like Lamb could be forced to leave the country to find the help they need, Pastine said. Switzerland offers assisted deaths to foreigners, but travelling overseas isn鈥檛 always an option.

鈥淔or some people, that might be a possibility. For others, it鈥檚 simply too expensive, they鈥檙e too sick, they don鈥檛 want to die away from their families, as I think any of us could understand,鈥 she said.

With files from The Canadian Press