As far as weddings go, this one was a long time coming.

Key points: Kirby and Johan van Vloten met in Sydney on February 11, 1969

Kirby and Johan van Vloten met in Sydney on February 11, 1969 Kirby initially wanted to boycott the same-sex marriage postal vote

Kirby initially wanted to boycott the same-sex marriage postal vote They decided to marry to show their relationship is not "second class"

Exactly 50 years to the day since they first met, former High Court judge Michael Kirby has married his longtime partner Johan van Vloten in a civil ceremony in Sydney's Bondi Junction.

In an interview on Radio National ahead of the nuptials, Mr Kirby said the pair had met at The Rex Hotel — one of Sydney's few gay venues in 1969.

"He came in at about quarter to nine and the relationship that was made that night lasted from that moment on really, and it's still going strong."

Celebrant Michelle Bailey told wedding guests that within weeks of the fateful meeting the pair had been introduced to, and accepted by, their respective families.

Within a year, they had embarked on the first of two long overland trips to Europe in a Kombi van.

"By this, they explored the world and each other," she said.

"They liked what they discovered."

Michael Kirby and Johan van Vloten in Fiji, in July 1969, five months after they met. ( Supplied: Michael Kirby and Johan van Vloten )

Given their 50 years together, the couple did not "feel a special need to secure a document from government," Ms Bailey said.

"Shared love does not seek permission from officials for its existence.

"At this stage, they did not feel that they had anything to prove about their love.

"Fifty years and counting says it all."

Their marriage was "proof positive of the capacity of love to prevail over obstacles, hostility, change and the passing of time," Ms Bailey said.

Over the years, the pair endured the loss of family members. They also lost friends to "the scourge that was, and still is, AIDS," she said.

"Johan added support, common sense and practical wisdom to Michael's approach to life, the law and the other problems they faced together.

"Johan has kept them both laughing and solving life's problems … whenever there has been an argument, Michael has always given in and taken the blame.

"These things are not expected to change."

Guests were treated to a cello rendition of Standchen from Schwanengesang by Schubert before the pair exchanged traditional vows, "for better, for worse, for richer for poorer … till death us do part".

Johan van Vloten and Michael Kirby in Rose Bay in 1996. ( Supplied: Michael Kirby and Johan van Vloten )

Ms Bailey — who also works as a research scientist at The Kirby Institute — told guests that she had first reached out to Mr Kirby "on a whim" around the time of the Government's same-sex postal vote, to offer her services should he and Mr van Vloten decide to marry.

She described her offer as a "small gesture to give back in appreciation for all Michael and Johan have done for the HIV and same-sex community, despite not having the human right to wed during 49 years of their lives together".

Mr Kirby, who served on the High Court from 1996 to 2009, had initially wanted to boycott the postal vote, but changed his mind and voted "yes".

He told RN the pair had been "rather skeptical" about marriage, after seeing many gay friends tie the knot, then later divorce.

They did not want to say in any way that their long relationship was "second class".

"When gays started to get married they started to fall out and act just like straights — it was really a big worry and we weighed up every possibility, and then we've decided to take the plunge.

"The 50th anniversary was just too romantic for us to let go."