Preliminary results for the cannabis legalisation and euthanasia referendums will be out today.
But it will be another week before the official count is announced, along with special votes, on 6 November.
Unlike recreational cannabis, the assisted dying referendum is binding.
Catherine Marks was the lawyer for euthanasia campaigner Lecretia Seales, and helped draft the End of Life Choice Bill.
She told Morning Report she was optimistic the polls would be in favour of the bill.
"The polls have been pretty consistent around 60 percent which suggests that it will be a positive initial result today."
She said the Act had already been passed.
"Soon as you have the final result which is on 6 November, it becomes law and it comes into force 12 months later."
Marks said the delay was to enable setting up the law, including setting up a list of doctors, a registrar, and a review committee.
In Victoria, Australia it took 18 months. She said in its first year reports, 124 people used it, and there were 272 applications.
"Almost all of them had terminal cancer, they were near the end of their life and the regulator of the Act there said she looked for coercion ... didn't find any type. But what she did find were people who were really grateful, the feedback she said had been predominantly how peaceful it was.
"... we're going to see the same sort of responses in New Zealand. This Act isn't about ending people's lives, it's helping dying people have a better death."
As a for a review for the law in New Zealand in three years' time, she said Oregon in the US had not made any changes in 23 years.
"This is a very strict bill but we'll see what the feedback is and if there are any issues about access that will be something for Parliament to consider in the future."
Anti-euthanasia group Care Alliance secretary Peter Thirkell said in countries like the Netherlands and Canada there were legislation changes brought in gradually and that was a concern.
"We believe it's inevitable this legislation will increase over time. It will have ... not good effect on the practice of palliative medicine."
He said opposition to the law would continue.
"We believe that the safeguards aren't merely adequate or sufficient. That place people in vulnerable circumstances at risk and there are other concerns.
"We would certainly want to see some emphasis on strengthening the safeguards, particularly around coercion and pressure."