The bodies of Ms Blake and a 30-year-old man were discovered in a unit above a restaurant on Newtown's King Street about 5.30pm on Friday, January 12.

Police were called to the unit when a friend raised concerns for the pair's welfare, where they discovered the bodies.

Investigators were treating the deaths as a murder-suicide, and a police spokeswoman said the nature of the relationship between Ms Blake and the 30-year-old man would form part of their investigation.

Ms Blake had travelled to Sydney just after Christmas after finishing three months' work harvesting citrus fruit on a farm in the north-western Victorian town of Colignan.

Mansell Farms owner Robert Mansell said he, his family and Ms Blake's former colleagues were "in shock".

"I'm getting messages from people who worked with her saying 'tell me it's not true'," he said.

"She was just an absolutely lovely girl; a good worker, she had the smarts, she was organised, happy. Just a lovely girl."

Mr Mansell said his thoughts and prayers were with Ms Blake's family.

"It's really upsetting. I've had kids overseas and you just hope someone's looking after them," he said.

"We treated her like family."

A lifelong friend of Ms Blake's in the UK wrote of receiving the "tragic" news of her death.

"This has broken my heart into a million pieces," Rhys wrote on Facebook.

"It's almost unimaginable that I'll never see you again, my dear friend. Until we meet again. I love you to the moon and back.

"My Love always. Rhysie Boy."

Another British friend of Ms Blake's wrote she was devastated by the loss of such a bubbly, loving and down-to-earth woman.

"The way she has been taken from this world was unthinkable and breaks my heart every time I think about it," Emily wrote.

"An angel taken to early. All my thoughts are with you."

Social media posts from last year show Ms Blake in Victoria with other backpackers, who had been working as fruit pickers in the state's north-west.

Comments on Instagram from Ms Blake indicate she was also planning a possible trip to Bali.

"I see my path, but I don't know where it leads. Not knowing where I'm going is what inspires me to travel it," she wrote on her Instagram page.

Police have established Strike Force Tenisonwood to investigate the deaths.

The strike force is made up of officers from the Newtown Local Area Command and the State Crime Command's Homicide Squad.

A police spokeswoman could not detail the injuries the pair had, or what had caused their deaths.