Voluntary assisted dying is a step closer in Tasmania after legislation to legalise the practice passed the state's upper house.

Tasmania has moved closer to legalising voluntary assisted dying, with the landmark legislation passing one chamber of parliament.

The bill was on Tuesday voted through the state's upper house where it was introduced, but must still be passed by the House of Assembly to become law.

"This legislation is simply aimed at helping individuals suffering intolerably find peace," said independent upper house member Mike Gaffney, the bill's architect.

It is the fourth attempt to introduce such laws, after similar legislation was defeated in 2009, 2013 and 2017.

Liberal Premier Peter Gutwein told parliament that lower house debate would begin this year, but not finish until March.

He has asked the University of Tasmania to examine the bill and compare it to assisted dying laws in Victoria and Western Australia, as well as other countries.

"It is incumbent on all of us to ensure this is the best law possible and it affords real protections to the most vulnerable in our community," he said.

The bill appears likely to have the numbers needed to pass the lower house.

Labor and the Greens, which have 11 members of Tasmania's 25-seat lower house, have indicated their support, while Liberal members will be given a conscience vote.

Liberal Speaker Sue Hickey, who doesn't vote along party lines, has indicated she backs the bill.

"There are many in this house who would prefer that the legislation be debated and passed this year, but we understand that is not possible," Greens leader Cassy O'Connor said.

"We believe the legislation will pass. People recognise this is a necessary reform and it comes from a place of deep, deep compassion and respect for human dignity and autonomy."

Critics, including Tasmania-based group 'Live & Die Well' have raised concerns the bill doesn't properly protect vulnerable people.