Linda Lingle, the Hawaii governor who vetoed a civil unions bill last week, has compared them to condoning incest.

The bill had passed both houses and would have given both straight and gay couples the right to have their partnerships recognised with all the rights of marriage.

However, Ms Lingle blocked it, saying she thought the move was “essentially same-sex marriage by another name” and added that the decision was “so important it should be decided by the people”.

Speaking last Thursday morning on Rick Hamada’s radio show, she was apparently unaware that first cousins are permitted to marry in the state.

She said: “For those people who want to make this into a civil rights issue, and of course those in favour of the bill, they see it as a civil rights issue. And I understand them drawing that conclusion.

“But people on the other side would point out, well, we don’t allow other people to marry even — it’s not a civil right for them. First cousins couldn’t marry, or a brother and a sister and that sort of thing.

“So there are restrictions, not to put it in the exact same category. But the bottom line is, it really can’t be a civil right if we are restricting it in other cases, and it’s been found to be legal in those other cases, that the restrictions [are constitutional].”

According to the Honolulu Civil Beat, one caller questioned why Ms Lingle was apparently unaware of her own state’s laws on marriage and the Health Department confirms that first cousins may marry.

Lambda Legal and the American Civil Liberties Union of Hawaii have said they will sue the state over the veto and have readied a lawsuit.

Laurie Temple, staff attorney for the ACLU, said: “We’re obviously disappointed that Governor Lingle has, once again, used her power to deny the people of Hawaii their civil rights.

“Luckily for the people of Hawaii, however, our constitution prevents discrimination based on sexual orientation. If the governor won’t honour her oath to uphold the constitution, the courts will.”