(Reuters) - Hawaiian Governor Neil Abercrombie called on Monday for a special legislative session next month to pass a bill that would legalize gay marriage in the strongly Democratic state that already allows same-sex civil unions.

State legislators presented a draft bill last month to allow same sex marriages in Hawaii, building on national momentum to allow gay nuptials after the U.S. Supreme Court in June invalidated part of a federal law defining marriage as between a man and a woman.

"The decision to call a special session is based on doing what is right to create equity for all in Hawaii," Abercrombie said in a statement, calling on both houses of the state legislature to convene in special session on October 28.

Abercrombie, a Democrat, said a special session would allow the legislature to "focus squarely" on the issue, without having to divert attention to the hundreds of other bills introduced during a regular session.

"In addition, if full advantage of various tax and other financial issues for citizens is to be achieved, passage before the end of the calendar year is essential," he said.

Should lawmakers pass the measure, Hawaii would join 13 other U.S. states and the District of Columbia in recognizing gay marriages outright.

(Reporting by Tim Gaynor in Phoenix; Editing by Cynthia Johnston and Mohammad Zargham)