Ben Jago's partner Nathan Lunson took his own life in 2015.
"He was just a lovely, sweet person who made me happy," Mr Jago said.
They had been together for more than five years and owned a house, but when Mr Lunson died, the coroner denied Mr Jago senior next-of-kin status.
According to , a relationship can be proven if it is registered, or if certain circumstances are taken into account.
Nathan Lunson, left, died in 2015. Source: Supplied, Ben Jago
These circumstances include the duration of the relationship, common residence and ownership of property.
The coroner named Mr Lunson's mother as his next-of-kin, instead of Mr Jago.
Mr Jago wanted to challenge this decision, but this week the Tasmanian Supreme Court determined the coroner's office is immune to discrimination complaints.
Ben Bartl is a solicitor with the Hobart Community Legal Service, and said despite same-sex marriage being legal in Australia since 2017, this could happen again to couples that are not married.
"We believe it is a travesty of justice," he said.
Ben Bartl is a solicitor with the Hobart Community Legal Service. Source: SBS News: Sarah Maunder
"We believe that Ben should have had an opportunity to present his case before the Anti-Discrimination Tribunal, and to argue that the coroner’s office had acted in bad faith against Ben."
Rodney Croome is a spokesperson with Equality Tasmania.
He said gay couples are sick of having to prove themselves, and their relationships.
"Many LQBTQ people experience stigma of being told that we have to prove who we are, that our relationship’s aren’t valid and we need to go that extra mile, Australia said yes to equality, that’s what we deserve across this nation, and we are not going to allow the Tasmanian coroner to stand in the way of that."
Mr Croome said Equality Tasmania will demand an apology from the Tasmanian government.
"We will be asking for three things: an apology, redress for the trauma that Ben Jago has experienced, and for amendments to the coroner’s act to make it absolutely clear that all relationships must be treated perfectly equally in Tasmania."
Rodney Croome said the Coroner's decision not to name Ben Jago as next-of-kin was "flat-out discrimination." Source: SBS News: Sarah Maunder
In a statement, Tasmanian Attorney-General Elise Archer expressed her condolences to Mr Jago.
"The court has now published its judgment upholding the decision of the anti-discrimination appeal. I am now seeking further information from my department on the outcome of this decision and will of course consider its implications," she said.
A protest to show solidarity with Ben Jago will be held outside the coroner's office in Hobart on Friday, 19 March.
Readers seeking support can contact Lifeline crisis support on 13 11 14, Suicide Call Back Service on 1300 659 467 and Kids Helpline on 1800 55 1800 (for young people aged 5 to 25). More information is available at and . supports people from culturally and linguistically diverse backgrounds.
