For less than a week in 2013 same-sex couples were able to marry in the ACT before the laws were thrown out by the Australian High Court.

The 31 couples who married in the brief five-day window before the ruling had their marriages declared invalid.

At the time of the ruling then-ACT Chief Minister Katy Gallagher said she was disappointed the court had not found in the ACT's favour after the "long hard road" that had been fought to end discrimination for same-sex couples in the capital

But British citizens have been able to legally marry a partner of the same sex since changes to the UK Marriages Act were introduced in June 2014.

Jenny Seymour and the love of her life Jeannette Walsh were travelling in Europe when they first discovered Jeannette's British citizenship would enable them to marry legally at home in Canberra.

"We began planning immediately," Jenny said. "As soon as we were back at home in August we went in and lodged a notice of our intent to marry."

On September 26, 2014, surrounded by family and friends at the British High Commission the two officially got hitched – the fifth same-sex couple ever to do so in the ACT.

"It was so nice to have everyone we love there, and after all this time I can call Jeannette my wife," Jenny said.

"Everyone at the High Commission was so helpful, right down to the security guards. The ceremonies are all pretty new for everyone but I don't think more could have been done to make us feel supported."

The Dunlop newlyweds felt privileged their spring wedding last year at the High Commission in Yarralumla would stick.

Although their nuptials would give them legal marital status in Britain, Australian law does not recognise the union.

The two women are both career public servants. They met in 1999 while partying in Sydney and have spent their lives together in Canberra ever since.

Jenny, who has two sons Aaron, 27, and Nathan, 24, from her first marriage, said this time around organising the big day was much more simple.

"This time there were no bridal dresses and far less fighting between in-laws," she joked.

"We both carried bouquets but I don't think I could ever get Jeannette into a dress."

Dual UK and Australian citizen Paul Eldon and his Adelaide-born fiance Dan Sanderson have spent the past five years together in Canberra.

The two plan to wed at the British High Commission in March and are busily planning their celebration.

"We couldn't do it if one of us wasn't British, but we wouldn't be doing it if it wasn't recognised by one of our governments," Paul said.

"I wouldn't go to Canada to get married or to New Zealand for example."

The 35-year-old said getting married was a personal choice but it was crucial to publicly exercise the equal right to marry afforded to him under UK law as a means to combat widespread discrimination.

"Our wedding doesn't really happen in Australia, it happens in a little slice of the UK here in Canberra," he said.

"Really it's a private event in our lives, but thinking about the bigger picture the more people that are have same-sex marriages the louder the voice for change becomes."

British High Commission spokesman Alex Beatty said same-sex marriage ceremonies at the Yarralumla post were by no means a way to bypass domestic legislation, but a legal right available to the some 1.2 million Britons living in Australia.

In order to get hitched, at least one partner must be a British national and non-British partners need to obtain a certificate of no impediment to marriage from national authorities, which Australians need to seek from the Attorney-General's office.

"Once the marriage register is signed couples can exchange rings, make promises to each other, and if they have a special request we are flexible enough to consider including it," he said.

"However, because it is a civil ceremony we cannot include anything political or religious."

Australian Marriage Equality deputy director Ivan Hinton-Teoh said it was evident the federal government's attempts to prevent same-sex marriage occurring on Australian soil were futile.

"Marriages of two people of the same sex are occurring all over the world but they are also occurring here in Canberra," he said.

"The continued resistance of the Australian government to celebrate them is an act of futility and hard-heartedness because the ongoing impact that our current policy has on same sex couples all around Australia is very real and damaging."

Mr Hinton-Teoh said news the United States Supreme Court would rule on a national debate over same sex marriage in the next few months was evidence the tide was turning worldwide.

"With all of the progress that is being achieved internationally, and the emergence of the very likely possibility that marriage equality may be rolled-out nation-wide in the United States, it demonstrates that Australia is falling so far behind on this critical social justice issue."

Since the facility for same sex weddings came into effect six months ago 60 same sex marriage ceremonies have been held at British consular posts in major cities across Australia

It has also been possible to convert from civil partnerships to same sex marriages since December – more than 20 of these formal ceremonies held in Australia so far.