The Washington state Senate has approved a bill that expands an existing domestic partnership law to give gay and lesbian couples all the benefits of marriage except the name, reports The Associated Press.

Senators passed the measure on a mostly party line 30-18 vote Tuesday. The bill now heads to the House.

The 110-page bill expands benefits offered by a 2007 domestic partnership law to include all remaining areas currently only granted to heterosexual married couples.

The bill is being sponsored by openly gay Senator Ed Murray, a Seattle Democrat who sponsored the state's domestic partnership law in 2007, while openly gay Rep. Jamie Pedersen (D-Seattle) is sponsoring the measure in the House.

Washington state lawmakers defined marriage as an institution between a man and a woman when it banned gay marriage in 1998. In 2006, the Washington Supreme Court upheld the legality of the law.

Last year, lawmakers successfully passed a bill that greatly expanded the partnership protections, moving from only 11 rights to over 170.

“You have denied us that right [of marriage],” Murray is quoted by the AP. “Do not deny us the right to care for our families and build our lives.”

The bill is expected to face little resistance in the Democratically led House, where 60 out of 98 representatives have already signed onto the bill. Washington state Governor Christine Gregoire, a Democrat, has expressed her support for the measure. Gregoire, who assumed office in 2005, signed the 2006 domestic partnership law, and the two previous expansions in 2007 and 2008.

Opponents of the measure say the state's domestic partnership law redefines marriage. If passed, the measure is likely to face a challenge with opponents claiming it violates the state's gay marriage ban.

“Same-sex couple have the right to form meaningful relationships. But I don't think they have the right to redefine marriage for all of us,” Senator Janea Holmquist, a Republican from Moses Lake, told the AP.