Members of the Welsh Senedd will on Tuesday decide whether to give their consent to Kim Leadbeater MP's assisted suicide bill.
The House of Lords is currently debating the controversial Terminally Ill Adults (End of Life) Bill, passed by the Commons last year.
The bill is facing considerable opposition in the Lords but if passed would legalise assisted suicide across England and Wales for terminally ill adults with less than six months left to live.
As health and social care are devolved matters, the UK Parliament normally seeks the Senedd’s consent before any bills affecting these areas can apply in Wales. It is incredibly rare for the Senedd to refuse to give its consent and doing so would stoke tensions with Westminster.
Christian advocacy group, CARE, is urging Senedd members to reject what it calls an "irredeemably flawed" bill.
CARE CEO, Ross Hendry, who is Welsh, said the bill had been "exposed, at times brutally so, in the House of Lords especially, as being riddled with problems".
"Legalising assisted suicide in Wales would open a Pandora's box and would put enormous pressure on the most vulnerable," he said.
"The Westminster Bill is an attempt to pass assisted suicide in Wales through the back door yet the Welsh people have given no such mandate and it wasn't that long ago that the Senedd actively voted against assisted suicide in a non-binding vote.
“By rejecting this motion, the Welsh Parliament would send a powerful signal to the most vulnerable in communities across the country, from Cardiff, to Aberystwyth, to Llandudno.
“Thanks to the power of palliative care, a good, pain-free death is possible without the ethical problems and complications that would inevitably arise from legalising assisted suicide.”
