A British woman says she's been forced to surrender her dream life in Australia, after discovering her birth certificate lists her as a boy.

Mother-of-five Kim Walmsey was mistakenly recorded as a male at her birth in 1965, meaning her marriage of 23 years was illegal.

"Our life in Australia was unbelievable and we’ve lost all that," the former Gold Coast resident told the Daily Mail after returning to her native England.

Upon discovering the mistake, Walmsey found herself unable to renew her Australian visa and spending over £150,000 on a mission to set things right in the UK.

Worse, when word got out in her Liverpool neighbourhood, Walmsey became the victim of homophobic slurs as neighbours believed she was in a gay marriage.

Kim Walmsley married husband Jack 23 years ago. Photo: Twitter/@kimwalmsley1

Kim told the Mail, “The whole thing is absolutely disgusting. I’ve lived nearly 40 years not realising I was actually registered as a boy and then all of a sudden my whole life fell apart.

“In the eyes of the law we were technically two men marrying and that was against the law at the time.

"Since I found out I have tried everything I can possibly think of to get it changed but it’s like banging your head against a brick wall."

Westminster sanctuary ruled her marriage to Jack, a security officer, was against the law, which was confirmed in a letter from the Arch Bishop of Canterbury in June last year, the Mirror reports.

“We live in a small community and we felt really intimidated. I don’t want people thinking I’ve had a sex change," she told the paper.

“Some people might think the kids are adopted and that I’m trying to hide the fact I’m a man.

“My death certificate will say I’m a boy too and so when I’m dead and buried, my family down the line will think there was this huge scandal.”

Walmsey’s MP Bill Esterson has written to UK Prime Minister David Cameron on her behalf.

"This is a ludicrous case of a mistake which was made nearly half a century ago, which is still plaguing Kim and her family today," he said.

"The fact that Kim is obviously a female is unquestionable. She has five biological children, but because her birth entry states that she is male, she is having these problems which are causing great distress to Kim and her whole family."