The bill passed the upper house with 22 votes to 18, after a marathon 28-hour sitting that began on Tuesday afternoon and ended just after 4pm on Wednesday.

Shortly before the final upper house vote, Member for Western Victoria Simon Ramsay, who had previously been undecided on the bill, rose to confirm he would support the bill with amendments. His support was crucial to the bill's survival. 

Upper house MP James Purcell, who voted in support of the bill, said it had been a long process to reach a decision.

“We sat for somewhere between 27 and 28 hours,” he said. “It was a long process we had to go through.”

He said the opponents were keen to ask all and any questions they could about the legislation.

“It was a long night and it follows on from the long night we had last week, but i am glad for the result,” Mr Purcell said.

He consulted with the community before making up his mind on which way to vote.

Victoria is now poised to become the first Australian state to legalise such a scheme.

The bill will give terminally-ill Victorians in intolerable pain and with less than six months to live the right to ask to end their lives. That timeframe will be extended to 12 months for people with neurodegenerative diseases such as Motor Neurone Disease.

It will take 18 months for voluntary euthanasia to be introduced in Victoria.

There were emotional scenes in the upper house as MPs, who had debated the bill all night, wept in their seats or got up to embrace their colleagues. 

Greens MP Colleen Hartland wept into her colleague Samantha Dunn's shoulder as the final vote was declared. Ms Hartland, who is set to retire at the coming election, has been a long-time supporter of a voluntary euthanasia regime. 

Although the bill has already passed the lower house with a strong majority, it must go back in its amended form for a final vote.

Both government and opposition MPs were granted a conscience vote on the bill, freeing them from being bound by party lines.

The bill was debated by both houses of Parliament for about 100 hours. 

Supporters of euthanasia had sought to pass the bill in the upper house last week but Parliament was adjourned after Labor MP Daniel Mulino collapsed and was rushed to hospital after more than 24 hours of continuous debate.

Mr Mulino, who opposed the bill, returned to Parliament on Tuesday when the upper house was recalled to debate the legislation.

MPs struggled through the exhausting sitting as the government's leader in the upper house, Gavin Jennings, calmly answered questions on many of the clauses in excruciating detail.

Last week Liberal MPs Inga Peulich and Bernie Finn read out extracts of articles and documents in their contributions to the debate, frustrating supporters of the bill who accused them of unnecessarily delaying the final vote by "filibustering".

But many opposing rose to ask questions and point out their concerns with the bill at length as debate wore on.  

This week's sitting began on Tuesday afternoon and ran almost continuously through to Parliament's adjournment on Wednesday.

Victoria will become the first state in Australia to allow people to end their lives through the voluntary euthanasia scheme.

The Australian Medical Association said the passing of the legislation marked a significant shift in medical practice in Victoria. 

"The outcome of this parliamentary vote will cause anguish for some members of our profession, as well as the public," AMA Victoria president Lorraine Baker said. 

She said the AMA believed doctors should not be involved in "interventions that have as their primary intention the ending of a person's life".

But Dr Baker said the conscientious objections provisions contained in the legislation ensured doctors would not be forced to be involved in voluntary assisted dying against their wishes.