The ACT Government says same-sex couples will be able to get married in Canberra before the end of the year, with the introduction today of the Marriage Equality Bill into the Legislative Assembly.

If successful, The ACT will become the first Australian jurisdiction to legalise same sex marriage.

The bill is expected to pass during next month's sittings with the support of Greens Minister Shane Rattenbury and all eight Labor MLA's.

Chief Minister Katy Gallagher says same sex couples will be able to marry in the ACT well before the end of the year.

"We went to the election seeking to be the most LGBTI (lesbian, gay, bi-sexual, transgender, intersex) friendly community in Australia," she said.

"This I think positions us well."

It is not the first time the ACT has tried to legislate for marriage equality, with the Civil Unions Bill quashed by the Howard government in 2006.

But after legislative changes, it will now be much harder for the Federal Government to overturn the law because it will need a vote in both houses of Parliament.

But it is highly likely the bill will be challenged in the High Court.

Ms Gallagher says she is aware some are opposed to the bill.

"It comes with risks about potential challenges to the legislation but again we don't believe that should stop us pursuing a commitment we have made.