A judge has turned down a couple's attempt to have their marriage declared null and void because the wife was unaware her husband identified as a female when they made their wedding vows.

The couple were to all appearances a man and a woman when they married in 1998, though the partner with male genitalia – who was listed as the respondent to the court application – always privately identified as female.

Australians voted to allow same-sex couples to marry in in November 2017. Credit:AFR

The biological female was aware her partner enjoyed dressing up in women's clothing and their sexual experiences sometimes involved them dressing as a female, but she told the Family Court that she always thought of her husband as a man.

"I had no inkling that he was not thoroughly male, but was in fact, a transgender female who since the age of six has outwardly denied her female gender identity; burying her true self under a quirky, hyper-masculine rendering of a man," she said.