Doctors opposed to the right to die will be allowed to opt out of helping terminally ill patients end their lives, under a key concession included in a revised bill due to be tabled later this week.

Right to die campaigner Lord Joffe will publish a revised version of his patient (assisted dying) bill in order to address some of the concerns raised by his critics.

Changes include a beefed up "conscientious objector" clause for doctors opposed to the principle of helping terminally ill patients to die, and a decision to drop voluntary euthanasia from the bill, following a recommendation made last May by a select committee of peers.

Voluntary euthanasia is where a doctor administers a lethal dose to a patient who has requested the right to die with dignity.

This means healthcare professionals faced with a terminally ill patient requesting to die will only be required to assist them by handing them the drugs to self administer.

Many doctors opposed the provisions made in the original bill, which they believed a placed a duty on them to raise assisted dying as one of the option available by terminally ill patients, if the new bill became law.

Professionals feared this could introduce a concept to patients they would never otherwise have thought of, and apply an unwitting element of pressure.

The bill now states that "no person shall be under any duty to raise the option of assisted dying with a patient".

Speaking exclusively to SocietyGuardian.co.uk ahead of the bill's publication, Lord Joffe said. "It has always been for the patient to ask for assisted dying but what we are making clear is that it is not necessary for a doctor to raise assisted dying with a patient if he or she does not want to do so."

The bill no longer provides duty on healthcare professionals to refer the patient on to another colleague who does not have a conscientious objection.

"Before, if a doctor had a conscientious objection he had to refer the patient to another doctor . They felt they were being asked to participate," Lord Joffe said.

"The bill now says that the person shall be under no duty to participate in diagnosis or treatment or referral or any action authorised by this act to which he has a conscientious objection. We make it very clear there is no pressure on doctors."

This provision covers all healthcare professionals involved in a terminally ill patient's care, he added, including nurses and pharmacists

Hospices, hospitals and other healthcare establishments would also have no statutory obligation to allow the assisted death of terminally ill patients on their premises, under the terms of the new bill.

This was to "take the on board the legitimate concerns that if you have a terminally ill patient to be helped to die in a hospice it could be unsettling for other patients," Lord Joffe said.

It will be up to the patient to seek out a healthcare professional who can talk them through the assisted dying process.

In the US state of Oregon, upon whose practices the assisted dying model is based, an organisation has been set up to advise patients on their right to die with dignity.

The organisation, Compassion on Dying, also advises healthcare professionals, many of whom will only experience one or two cases of assisted dying in their entire professional lives.

Lord Joffe, however, has stood firm on one contentious thread of his bill by insisting that the criteria which allow assisted dying for terminally ill patients experiencing "unbearable suffering" be kept.

The select committee had called on Lord Joffe to replace "unbearable suffering" with "intractable suffering", but the cross-bench peer disagrees.

"It would mean it would be compulsory for the patient to have first tried palliative care and there a small number of patients who would say they do not want palliative care. They are actually ready to die. It would be contrary to the principle of personal autonomy on which the bill is based."

Despite tabling the bill for the fourth time in three years, Lord Joffe believes the mood on assisted dying has shifted since he first introduced it in 2003.

The issue gathered momentum following the high profile case of motor neurone disease sufferer Diane Pretty. Ms Pretty fought an unsuccessful battle in the European Court of Human Rights to be helped to die by her husband before she faced the swallowing and breathing difficulties that ensue in the last stages of the disease.

A debate on the select committee report on his bill in the house of Lords last month saw 75 peers line up to speak for and against for eight hours.

Surveys of public opinion over two decades show growing support. In a YouGov poll published in August, 86% agreed that people who are terminally ill should have the right to decide when they want to die and to ask for medical assistance to help them end their lives.

Last summer, the British Medical Association (BMA) dropped its opposition to doctors being allowed to help terminally ill patients to die in what was described as a "historic" decision..

Opponents of change argue that good palliative care should avoid the need to undergo a painful death.

Few bills tabled in the House of Lords make it to statute without government backing, however. So far, the government has remained quiet on the issue. But Lord Joffe is quietly confident the ground is shifting.

The government has remained neutral over the issue. "They say they are listening", he said. "and I think they are listening carefully".