Hawaii's governor has called a special legislative assembly next month to debate a bill legalizing gay marriage, in what would make it the 14th US state to do so.

Lawmakers in the Pacific island state will meet from October 28 to discuss a bill "to address the issue of marriage equity," said Gov. Neil Abercrombie (D), who in 2011 signed a law legalizing same-sex civil unions.

"The purpose of the Act as stated in the bill is to recognize marriages between individuals of the same sex ... and to address questions of equity, civilly and otherwise," he said.

"I've spent my entire life, politically, trying to find what's the fairest thing to do," he tweeted a short time later.

Attorney General David Louis said that, if the bill is approved, Hawaii could start issuing marriage licenses to same-sex couples from November 18.

Thirteen US states plus the capital Washington, a federal district, allow gay marriage.

In June, the US Supreme Court voted for the repeal of the defense of traditional marriage, which prevented same-sex couples from enjoying the same rights as heterosexual couples.

[Image via Gov. Neil Abercrombie Facebook page]