David Bulmer-Rizzi, 32, died in a fall Saturday while on vacation with husband Marco Bulmer-Rizzi, 38.
Because South Australia, the state where he died, does not recognize same-sex marriages from overseas, Marco Bulmer-Rizzi was told by state authorities the marriage would not be listed on the man's death certificate, and he would not be recognized as his husband's next of kin.
"It was a personal attack on David, on our memories. It was the most humiliating moment of my life," Marco told Australian public broadcaster ABC.
Reports of the bereaved man's ordeal triggered anger among social media users around the world and prompted a swift response from Australian authorities.
South Australia Premier Jay Weatherill told ABC that he was "deeply ashamed" by the episode and had personally apologized to the widower.
"A man's just lost someone he loves, his husband, someone he's legally married to, and he's treated with disrespect in my state," Weatherill said.
"It caused me to feel very sad. I reached out to him and contacted him and offered an apology for what he'd experienced here in South Australia."
He had intervened so that the "offensive description" of "never married" would not be included on the death certificate, he told the ABC.
Legislation would be passed so that overseas same-sex marriages were recognized in the state, he said, adding that the case highlighted the need for federal recognition of such relationships.
"This is a man who in death offered his organs for donation to South Australians to keep other South Australians alive and healthy, and here his partner has to put up with this level of disgrace," he said.
"This demonstrates that there is real hurt and pain caused when these relationships are not recognized," he said.
Same-sex marriage is not legal in Australia, although some states do legally recognize foreign same-sex marriages as state civil partnerships.
UK official praises commitment to change
The UK's high commissioner to Australia, Menna Rawlings, thanked Weatherill for his intervention and his commitment to change the state's law.
"My thoughts and deep sympathies are with Marco and everyone affected by David's death at this very difficult time," she tweeted.
Australian Sen. Robert Simms said in a statement that the case highlighted the need for law reform in Australia.
"We must reform Australian law to ensure no other person experiences this kind of trauma in the future," he said.