Supporters of Victoria’s proposed assisted dying law believe it is now likely to pass the lower house, after a tense late-night session of parliament saw the defeat of an amendment that would have derailed the legislation.

The fate of the voluntary assisted dying bill will be decided on Thursday or Friday. The reasoned amendment proposed by the deputy premier, James Merlino – an opponent of assisted dying – would have deferred the consideration of the bill until inequities in palliative care were addressed, the lethal substances to be used were decided, the risks of “doctor shopping” were dealt with and issues of potential elder abuse were resolved.

A reasoned amendment outlines objections to the bill’s principles and proposes it be withdrawn or redrafted.

The state’s health minister, Jill Hennessy, urged the parliament to reject any delay. “We’re elected to make decisions, let us debate this bill, let us not defer it.”

At 11.27pm, the amendment was defeated by 47 votes to 39, with the debate now due to resume on Thursday. A second reading of the bill was moved and passed by 49 votes to 36, clearing the way for a final vote. Further amendments will first be proposed and debated.

The late-night session concluded two long days of often emotional speeches by parliamentarians, many of whom recounted harrowing personal experiences of the deaths of family and friends. One Liberal MP, Bill Tilley, said that assisted dying was akin to murder and that if passed, the parliament would have “blood on its hands”.

Other MPs expressed concerns that the bill did not have enough safeguards to protect vulnerable people from being coerced, that palliative care should be improved before assisted dying laws were considered, and that it was problematic that the lethal medication to be used was yet to be decided.

Supporters stressed that terminally ill Victorians were taking their own lives due to their suffering, often in horrific ways, and that assisted dying should be a choice in limited cases. It was already occurring in the form of doctors increasing pain relief which had the effect of hastening death, and by patients refusing food and treatment.

Hennessy said on Wednesday night that “we live an environment where at the moment we have things like terminal sedation where many patients will starve or dehydrate themselves to death”.

Hennessy has carriage of the bill, and she thanked the parliament for what she described as a respectful debate. She urged against any further delays.

“We are elected to make decisions ... let us debate this bill and not defer because there are those in the community that require us to address the many challenging issues associated with death ... that time is now,” she said.

If passed in the lower house, the bill will proceed to the upper house, where supporters of assisted dying believe they have more support. However, numbers are believed to be in flux, with the result not assured. MPs have a conscience vote on the issue.

While debate in parliament has been largely respectful, the issue has sparked tensions between the state and federal divisions of the Australian Medical Association (AMA). On Wednesday the Victorian branch of the AMA criticised its federal president Dr Michael Gannon after he disrespected politicians who told stories of their parents’ painful deaths during the debate.

Quick Guide Victoria's proposed assisted dying laws Show Who can apply? Victorian adults, with a progressive, advanced terminal illness and 12 months or less to live



Suffering must be deemed 'intolerable'



They must be of sound mind How will it work? Patients must make three, clear requests



They will be assessed by two experienced doctors



Those approved will be granted permits for lethal medications, which must be self-administered



A permit will be granted for doctors to administer medication only in cases where the patient physically cannot



Doctors do not have to be present when patients administer the medication



The process to apply and receive medication cannot take less than nine days



The Department of Health and Human Services will approve applications



An assisted dying review board will oversee each step of the process What are the penalties? Potential life imprisonment for a breach of the self-administration permit

Five years' jail and substantial fines for inducing someone to request the scheme



Doctors who suggest the assisted dying scheme to patients face a professional misconduct investigation Source: Victorian government



The legislation has been almost three years in the making and has included consultation with disability workers, palliative care specialists and legal experts. The bill was drafted following a parliamentary inquiry that recommended assisted dying laws last year, and the findings of a ministerial taskforce headed by the former AMA president, Prof Brian Owler.

If passed, Victoria will become the first state to legalise assisted dying, which will be available for terminally ill people who are expected to die within 12 months. They must be adults, have requested assistance to die at least three times, and be an ordinary Victorian resident. The Northern Territory’s short-lived Rights of the Terminally Ill Act was overturned by the federal parliament in 1997.