After years of heated debate and dozens of last-minute amendments, laws allowing terminally ill people in NSW to voluntarily end their own lives are expected to pass the state parliament.
The legislation has cleared the lower house and is expected to reach a final vote in the upper house on Wednesday, after members consider close to 100 late amendments to the bill.
Debate began just before midday and is expected to continue until midnight.
Independent MP for Sydney and architect of the legislation, Alex Greenwich, is hopeful the bill will finally pass after years of campaigning.
"Today is a really important day in NSW," he told Sydney radio 2GB.
"We hope that by the end of it people with cruel and advanced terminal illnesses will have the same end of life care offerings as people in every other state."
Some 92 amendments to the bill have been proposed, and will be debated in blocks in the upper house before it goes to a final vote.
Labor MLC Greg Donnelly proposed more than 30 amendments, including that terminally ill patients with mental illnesses including bipolar disorder or depression should not be able to access voluntary assisted dying.
"If there is impairment there at all, that should be red flagged," Mr Donnelly told the upper house on Wednesday.
"That should be seen, my submission is diagnosed, ideally, but my submission is, picked up, at the earliest stage of this procedure."
Mr Donnelly also asked that wording be changed so terminally ill patients must communicate clearly and unambiguously.
He says the changes will lessen the risk of wrongful death.
NSW Opposition Leader Chris Minns said he was not aware of what the amendments moved by Mr Donnelly were, but did not agree it was a delaying tactic.
"The best way for the NSW parliament to deal with a large number of amendments is to sit continuously until the legislation is passed.' Mr Minns said.
Further proposed amendments include allowing residential aged care facilities and hospitals to ban their residents or patients from accessing voluntary assisted dying.
A poll conducted by Go Gentle Australia has found three quarters of NSW residents support dying people having access to all legal medical treatment options within their own home, including aged care facilities.
Some 74 per cent said terminally ill people living in aged care should not be blocked from accessing voluntary assisted dying by their provider.
If the bill passes on Wednesday unamended, voluntary assisted dying is likely to become available to terminally ill people in NSW in 18 months.
If the bill is amended it will have to return to the lower house on Thursday for approval.