Just under half of voters in Hawaii want gay marriage to be legalised, a poll says.

Public Policy Polling found that 49 per cent back gay marriage, 40 per cent oppose it and 11 per cent are unsure.

According to KITV.com, support was much higher when civil unions were given as an option and 77 per cent of respondents backed some kind of legal recognition for gay couples.

Of these, 90 per cent were Democrats, 77 per cent were independent voters and 59 per cent were Republicans.

In February, Hawaii’s governor Neil Abercrombie signed a civil unions bill.

The first ceremony will take place on January 1st and the measure will give gay couples almost all of the rights of marriage.