Rye Hunt's family say he was loyal, loving and an "infuriating!" brother after his body was found on a Brazilian beach.
Clinical tests confirmed the body washed ashore at Marica was that of Mr Hunt, an Australian who went missing in Rio on May 21. Mr Hunt's family on his father's side are New Zealanders.
"We are understandably heart-broken," Mr Hunt's sister Romany Brodribb said.
"Rye was the youngest member of our family and was known for being loyal, loving, generous, cheeky, and as a brother, totally infuriating!
"Thinking about life without him is unfathomable. He will be very missed by us all."
His partner Bonnie Cuthbert, who went to Rio to join the search for him, said she felt blessed to have shared her past five years with her "beautiful Big Bear".
"We have been so lucky to have found and loved each other so deeply. The love Rye and I shared will remain within both of us, forever."
The 25-year-old backpacker went missing on May 21 after he separated from his travelling companion Mitchell Sheppard at the Rio airport.
They had an argument after the two took what is suspected to be a highly potent hallucinogen known as NBOMe.
The family said on Facebook they were disappointed they weren't given the opportunity to share the sad news before it was announced to the media.
"We are understandably grief-stricken as we come to terms with the events of the past two weeks and will not be available for comment," a statement said, adding the family asked for their privacy to be respected.
Foreign Affairs Minister Julie Bishop said on Twitter the family was told immediately after the Brazilian authorities confirmed the test results overnight, and she answered a question from the media at midday.