The US state of Washington has signed into law a Domestic Partnership Expansion bill that will provide more than 160 new rights and responsibilities to registered domestic partners.

The bill passed the state Senate on March 4th by a 29 to 20 vote and the House last month by a 62 to 32 vote.

Governor Chris Gregoire signed the bill into law yesterday. It comes into effect in June.

It builds on a 2007 law, which created a domestic partner registry and provided specific rights and responsibilities for both same-sex and opposite sex couples.

“The Domestic Partnership Expansion bill provides significant protections to LGBT families while we continue the struggle for full marriage equality in Washington state,” said Joshua Friedes, Advocacy Director for Equal Rights Washington.

The Human Rights Campaign, America’s leading LGBT rights group, said:

“HRC congratulates Equal Rights Washington on this important step forward and thanks Governor Gregoire and fair-minded legislators for taking action that promises real benefits for same-sex couples in Washington and their families.

“This new law will provide vital rights and benefits for same-sex couples and their families.

“For the second time in as many years, the state of Washington has helped move same-sex couples toward full equality.”

In all nine US states have gay and lesbian spousal rights in some form: Connecticut, Oregon, Vermont, New Hampshire, New Jersey, Maine, California, Washington and Hawaii.

Only Massachusetts has legalised full gay marriage.