Six gay couples in Hawaii are filing a lawsuit Thursday asking for the same rights as married couples, three weeks after Gov. Linda Lingle vetoed a same-sex civil unions measure.

The lawsuit doesn't seek the titles of "marriage" or "civil unions" for gay partners. Instead, it requests that the court system extend them the benefits and responsibilities of marriage based on the Hawaii Constitution's prohibition against sex discrimination.

"We continue to be discriminated against," said plaintiff Suzanne King, who has been in a relationship with her partner for 29 years. "We're a family unit, and we live our lives just like everyone else, but we aren't treated the same."

The legal action in state court comes as a response to the Republican governor's veto July 6, when she said voters should decide whether to reserve marriage for couples of a man and a woman.

Five other states and the District of Columbia permit same-sex marriage. Five more states essentially grant the rights of marriage to same-sex couples without authorizing marriage itself.

Hawaii passed the nation's first "defense of marriage" constitutional amendment in 1998, giving the state's legislature the power to reserve marriage to opposite-sex couples. The amendment is silent on civil unions and rights for same-sex couples.

Most Hawaii residents don't want the government to endorse equal rights for gay couples, said Garret Hashimoto, chairman for the Hawaii Christian Coalition.