ACT leader David Seymour is about to unveil his End of Life Choice Bill.
He drafted his voluntary euthanasia legislation after a petition carrying 9,000 signatures was presented to parliament in June, asking for an inquiry.
In July, the health select committee announced it would hold an inquiry, and it's due to start hearing submissions on the petition on Wednesday.
When the petition was presented by the Voluntary Euthanasia Society of New Zealand, Mr Seymour said drafting a bill was "the right thing to do".
"It's a cruel choice to leave people choosing between a painful natural death, or their own potentially hazardous suicide," he said.
Mr Seymour will unveil his bill at a press conference on Wednesday morning.
The petition followed publicity around the plight of Wellington lawyer Lecretia Seales, who died from a brain tumour just hours after the family were advised the High Court had ruled against her bid to choose when she could die.
Prime Minister John Key has ruled out a government-backed euthanasia bill, and says it's a conscience issue for MPs.
Mr Seymour's bill is a member's bill, which means it has to go into a ballot.
There are about 70 already in the ballot box, and one or two are usually drawn every second Wednesday parliament sits.
Mr Seymour can ask parliament to allow him to introduce the bill and have it debated without it being drawn from the ballot.It's unlikely to be put on the fast track while the cross-party select committee is holding its inquiry.