The Christian charity CARE has said believers must speak out against the latest bill to be heard in parliament.
Labour MP Rob Marris' assisted dying bill receives its First Reading in the House of Commons later today.
It's widely expected he will take draft regulations drawn up by Lord Falconer in the previous parliament.
His proposed change to the law would have allowed doctors to prescribe a lethal dose to requesting patients who have six months or less to live.
It will be the first time MPs get to vote on the issue as all previous bills have gone through the House of Lords.
CEO of CARE Nola Leach drew a parallel with the 1967 Abortion Act, suggesting there was complacency amongst those who opposed abortion.
She said: "Christians have always understood that life is a gift from God and therefore it is undeniably precious.
"It is the duty of the law to protect people and to protect the value of life so legalising assisted suicide is a change to the very nature of the role of law itself.
"History gives us a very clear warning because if you think back to 1967, many people did not think legalising abortion would have the sort of disastrous consequences it has done.
"Maybe because previous attempts to legalise assisted suicide have been defeated, my concern is that if we sleepwalk into a situation where the law is changed and suddenly, people can legally end their own life, to my mind this would be a tragedy.
"If we want to see this latest attempt to change the law on assisted suicide defeated and if we are serious about protecting vulnerable people, we must shun complacency and make our voice heard now."
Nola Leach speaking to Premier's Marcus Jones:
