B.C.'s civil liberties watchdog is suing the Canadian government in an attempt to reverse laws banning doctor-assisted suicide for seriously ill people.

The BC Civil Liberties Association lawsuit, filed in B.C. Supreme Court Tuesday, contends that laws prohibiting assisted dying deny people the right to make choices about their physical and emotional dignity.

"We want every Canadian to have a choice to have what they consider to be a good death," Grace Pastine, litigation director for the BCCLA, told reporters at a Vancouver press conference.

"Inflicting unbearable suffering on individuals, on dying patients who wish to end their lives, is unjust, unacceptable and unconstitutional."

The BCCLA is asking for changes to the Criminal Code that would allow mentally competent adults with incurable diseases the right to seek medical help to end their lives.

The lawsuit is filed on behalf of Lee Carter and her husband Hollis Johnson, Fort Langley residents who travelled with Carter's 89-year-old mother to Switzerland last year to help her end her life. Assisted suicide is legal in the European country.

Kay Carter suffered from the degenerative condition spinal stenosis, which left her in chronic pain, confined to a wheelchair and unable to feed herself. She died from a lethal dose of sodium pentobarbital on Jan. 15, 2010 after writing a farewell letter to friends explaining her choice to take her own life.

"My mother, Kay, was a lifelong supporter of the dying with dignity movement. She lived her life with passion, independence and resolve, and her independence extended to insisting that she would have choice and control over how she would leave this world," Lee Carter said in a release.

"I feel that I'm honouring her memory by participating in this legal challenge."

Carter and Johnson say that they've lived in fear of prison since they helped Kay end her life. Under current laws, helping anyone commit suicide is a criminal offence punishable by up to 14 years in prison.

Victoria physician Dr. William Soichet is also named as a plaintiff in the suit. He treats patients suffering from diseases like cancer, Huntington's disease and multiple sclerosis, and says he would be willing to help patients end their lives.

"Dr. Soichet considers the ability to participate in physician-assisted dying on request, in appropriate circumstances and where there are all the necessary safeguards in place, an important component of the provision of health care to grievously and irremediably ill patients," the lawsuit reads.

The Attorney General of Canada will have 21 days after being served with the claim to file a response.

'A profound shift in social thinking'

It's been nearly two decades since the last major legal battle on the issue of assisted suicide divided Canadians.

In 1993, the Supreme Court of Canada rejected activist Sue Rodriguez's appeal to invalidate the law prohibiting assisted suicide. Rodriguez suffered from amyotrophic lateral sclerosis, a debilitating terminal illness, and died the next year.

Pastine said Tuesday that a lot has changed in the meantime, including the legalization of assisted suicide in several European countries and three American states: Washington, Oregon and Montana.

"We believe that this time, the court will decide the issue differently. There's been a profound shift in social thinking in recent years on these issues," Pastine said.

Alex Schadenberg, director of the Ontario-based Euthanasia Prevention Coalition, says his organization is prepared to intervene in the lawsuit if necessary.

"What they're suggesting is that people are being denied, as they would say, the right to die in Canada. In fact, the law doesn't actually deny the right to die, what it does is deny somebody else the right to cause your death," he said.

"It prevents a form of elder abuse -- people being pressured subtly into euthanasia or assisted suicide."

The BCCLA's claim is one of two right-to-die suits filed this month in B.C. Supreme Court. The Farewell Foundation for the Right to Die filed a claim on Apr. 8, also contesting the laws against assisted suicide.

The Farewell Foundation wants its members to have the legal right to help each other die.