Gay rights advocates have claimed a victory in Washington where the latest tally shows the state’s voters opted to allow increased rights for gay couples.

According to the latest unofficial returns, 72 per cent of the vote had been counted by yesterday afternoon, where the ‘approve’ campaign was running at 52 per cent.

AP reported that this vote makes history as it is the first time a state’s voters have approved a gay equality measure at the ballot box.

Referendum 71 will expand the state’s current domestic partnership law, essentially giving gay couples all the rights of marriage.

These include the right to use sick leave to care for a partner and rights related to adoption, child custody and child support.

The move will also give gay couples new inheritance rights.

It was due to come into power in June but was put on hold due after Protect Marriage Washington collected the 120,000 signatures needed for a referendum.

Washington has had domestic partnerships since 2007 and it is estimated that almost 6,000 have been carried out.