The father of international polo player Lauren Biddle says she was a "truly beautiful soul".
Ms Biddle, 22, died at a house on Spinnaker Ln near Sumner in Christchurch, just before 1am on Monday.
Emergency services were called by a friend of Ms Biddle's, who was performing CPR on her.
Police are treating her death as unexplained.
Ms Biddle, an American citizen, was working in New Zealand and was well known in polo fraternities in both countries.
Tributes have been flowing online, with the Palm Beach International Polo Club polo saying she was "a rising international polo player and accomplished horse woman".
Her father Tommy Biddle, a respect polo player himself, posted on Facebook saying "we lost an amazing young woman the other day. Lauren was a truly beautiful soul".
"We as a family have been overwhelmed with thoughts and support from around the world.
'I am truly amazed at how many people she touched in her short time here," Mr Biddle wrote.
"She did more in her 22 years with us then others do in a full life. She was my angel, my light, my girl. I have a huge hole in my heart."
Mr Biddle thanked everyone for their kind words, thoughts and prayers.
The United States Polo Association (USPA) says Ms Biddle's death has "shocked and saddened our polo family to the core".
In a statement provided to Newshub, the USPA says Ms Biddle was a "promising young player who will be lovingly remembered by the polo community as a passionate horsewoman, animal lover, adventurer and friend who lived life to the fullest".
"Her fun-loving spirit has left its impact on many, and her legacy will live on through those who play the sport that she loved so much. Our hearts go out to the Biddle family. Please know that you are not alone in your grief and the entire polo family is here for you during this difficult time."
The New Zealand Polo community reflected those views.
The South Island Polo Association says they were also shocked and saddened to hear of Ms Biddle's death.
"Lauren was known by many in our polo community and her fun-loving nature will be sadly missed. We send our thoughts and sincere condolences to the Biddle Family," a Facebook post reads.
Police say they have been in contact with her American-based family and are working with the US Embassy to offer them any support needed.
A post mortem was completed on Tuesday, and the results have been given to the Coroner.
Police and the Coroner are still awaiting toxicology reports.
A scene examination is still be carried out at the Spinnaker Ln address, which is expected to finish on Wednesday.
Newshub.
