Renee Duckmanton was last seen on Saturday night, and her work as a sex worker may have been a factor in her death, police say.
Ms Duckmanton's body was found on Main Rakaia Road at 7.40pm on Sunday night.
Police said a postmortem completed yesterday revealed that she had been burned. Her death is being treated as a homicide.
Detective Inspector Darryl Sweeney said as a result of information received by police, the last confirmed sighting of Renee was on Saturday night between 8pm and 10pm in the Manchester Street and Petersbourgh Street area.
"We now believe Renee's work in the sex industry may have been a factor in her death."
Mr Sweeney said police were reviewing CCTV footage from the area and talking to other sex workers who may have seen her.
Police asked for anyone who had seen Ms Duckmanton between 8pm and 10pm on Saturday night, including clients, to contact them.
"Even if it was just for a second, any little bit of information helps," Mr Sweeney said.
"The information we've received from the public has continued to be a significant help."
He said police would increase their presence in the Manchester Street area tonight where sex-workers operate.
Prostitutes Collective spokeswoman Anna Reed said she was shocked to hear of the young woman's death. She said the collective would go out to talk to and support other workers tonight.
"We'll talk to whoever we see and we're also trying to find out, of course, as the police are, who saw her last, when she was last seen and where."
Ms Reed said Ms Duckmanton's death was devastating.
"She was a beautiful young woman ... she had her whole life ahead of her."
Family pays tribute
In a statement released by police, Renee's mother Tracy said she would always be her beautiful baby girl.
"Renee was a kind, sweet and trusting person, with her friends and family.
"She was also bubbly, goofy and loved everyone she interacted with, she will always be remembered by her beautiful smile and will be missed by us all."
Renee's sisters Bianca and Jess described her as the best aunty in the world.
"She had a very easy-going nature and a gentle soul, Renee will always be in our hearts and remembered fondly by all who knew her."
The family said Renee's bright spirit would be missed by those who were blessed to have had her in their lives.
Police were at Ms Duckmanton's home in Cashmere today, and also at her mother's St Martins property.