Tasmania's Lower House could pass same-sex marriage laws by the end of the week.

Premier Lara Giddings has tabled a bill allowing same-sex couples to marry.

"The majority of Tasmanians believe the time has come for this change to occur," she said.

She has co-sponsored the bill with Greens leader Nick McKim, who says it is one of his proudest moments in Parliament.

"Today is a genuinely historic moment in Tasmania's history."

Debate on the bill is scheduled for Thursday.

Ms Giddings also described it as an historic moment.

"I certainly look forward to being able to present this bill with the leader of the Greens, containing an issue of course very important to many, many Tasmanians."

It will pass the Lower House without the support of the Liberal Opposition.

Sorry, this video has expired Tasmania’s premier confident marriage equality bill will pass

Opposition Leader Will Hodgman says the move is self-indulgent and a High Court challenge is inevitable.

Mr Hodgman told parliament Labor was aware of the legal risks and was trying to seek glory by siding with the long-held Greens' position.

"What have you been doing for the last 10 years that I've been in this place?"

"What did you do to act on these so-called discriminations then?

"You've been in government now for many years and presumably with the support of Greens members but you didn't act, you didn't act then but suddenly you are now.

"There's more than a whiff of self indulgence in all of this," he said, adding that he will not give Liberal MPs a conscience vote on the matter.

"It's the Australian Parliament that needs to make a decision about this matter."

Ms Giddings is calling on the Opposition Leader to allow a conscience vote.

"Have a conscience vote, allow one. Ask yourself for one because I would have thought that you would've been one of the progressive ones who would've understood how important it is to remove this discrimination."

Tasmania will become the first state in the country to legalise same-sex marriage if the bill is successful in the upper house.

Several independent MLCs have said they want to see the legislation before saying whether they will support it.