Brought up in Whanganui, she moved to London in August from Dargaville as part of an overseas teaching programme.
Her mother, father and sister flew to London to be by her side, while hundreds of people around the world have donated to a Givealittle page set up to help bring her home. So far, $38,101.50 has been raised from 529 donors.
Whanganui tennis prodigy Paige Hourigan was a school friend of Ms Kelly and described her as "the girl who was always smiling".
"She was the most fun to be around," said Ms Hourigan, who is from Turakina and is on a tennis scholarship at a US university.
"I remember just laughing and giggling with her all the time about nothing. She was a beautiful girl that will definitely always be remembered - especially for that smile."
Friend Lucy Griffiths wrote on the fundraising page: "Toni was a young, happy and beautiful girl.
"This money will help the family bring Toni home and pay for any extra expenses. Any donation - big or small - will be appreciated by all of her family and friends."
Kelly's sister Stacey Kelly took to Facebook to thank people who had pledged money.
"I just wanna say thank you from the bottom of my heart for the endless support so far.
"We are completely lost for words and can't wait to be home."
Friends and family continue to pay tribute to the young woman on social media, with one person describing her as "the most genuine, down-to-earth, free soul, crack-up chick I have ever met".
Dargaville High School sports co-ordinator Christine Taylor said she "was very sporty" and "very talented in photography and art".
Ms Kelly's friends in New Zealand held a tearful sunset ceremony on a beach near the family's home to mark her death.