Fewer than one in five doctors would be willing to help patients end their lives, according to a new poll.
Lord Falconer's Assisted Dying Bill - which is being considered by Parliament - would offer the chance of assisted dying to terminally ill patients deemed mentally capable and within six months of likely death.
But a survey of 600 doctors by the Medix consultancy found that 60% are against a change in the law to allow physician-assisted suicide.
This is a rise of 17 points from the last time the same question was asked - just 43% were against a change in 2004.
In the latest poll almost half of doctors said that in the last six months they have had at least one patient state they would rather die than stay alive.
Only 19% would be willing to help people die through legalised physician- assisted suicide or euthanasia, although 37% believe it is already happening anyway.
Half of doctors view terminal illness with uncontrollable physical suffering as an acceptable reason to carry out the procedure.
Dr Tony Calland, chairman of the British Medical Association's ethics committee, said: "There have always been strongly held views on assisted dying as this is a complex, emotive issue centred upon vulnerable patients nearing the end of their lives."
He added: "Doctors have repeatedly expressed their opposition to assisted dying when it has been debated regularly at the BMA's annual conference that sets our policy, which since 2006 has been to oppose assisted dying in all its forms.
"Many doctors have first-hand experience of caring for dying patients and believe that, rather than deliberately ending a patient's life, we should instead be focusing on building the very best of palliative care for those in distress."