The Tasmanian Parliament has heard passionate debate on a contentious bill to legalise voluntary euthanasia.

Lower House MPs, who have been given a conscience vote, put their views on the legislation for six hours before debate was adjourned for the night, with 12 MPs yet to speak.

The private member's bill, co-sponsored by the Premier Lara Giddings and the Greens Leader Nick McKim, would allow terminally ill Tasmanians to end their lives 10 days after making three requests to their doctor.

Ms Giddings told Parliament her grandmother's drawn-out death inspired her decision to co-sponsor the bill.

"She would frequently say, you know you can live too long, as she winced and screwed up her face through the shooting pain that would strike her body and which medication only seemed to over take the edge off for parts of the day," she said.

Mr McKim told MPs there were strict safeguards to prevent terminally ill people from being pressured into ending their lives.

He described the slow, painful death of Melbourne woman Angelique Flowers in 2008 to justify his push for legalised euthanasia.

"Her brother Damien held a bowl under his sister's chin as she vomited faecal matter before her death."

All 10 Liberal MPs have indicated they do not support voluntary euthanasia.

Liberal member Peter Gutwein says he understands the bill is well-intentioned, but has told Parliament his conscience will not allow him to support it.

"Not everybody out there has the best of intentions for those people that they profess that they love," he said.

"And I think any reasonable person could acknowledge that point, I haven't looked forward to making this contribution. I know that many here, it certainly won't satisfy or please them, but I can't support this bill."

Mr Gutwein's colleague Rene Hidding described the push to enact euthanasia laws as an elitist attack on Christians.

"It's time that people backed off on Christians who have a view about this matter," said Mr Hidding.

"My judgement this time on this law is that this is bad, dangerous, elitist law, Christian principle forbids me from legislating to endanger vulnerable Tasmanians."

At least three Labor MPs are likely to vote against the bill, including the Attorney General Brian Wightman, meaning it is unlikely to pass the Lower House.

A number of people were in the public gallery to watch the debate, including voluntary euthanasia supporter Dr Philip Nitschke.