The woman who died in mysterious circumstances in Christchurch on Monday has been named as American citizen Lauren Biddle.
Police said they had been in contact with her United States-based family. Biddle was working in New Zealand.
Tributes and kind messages for the family about the 22-year-old, who was well known in the polo community, have been posted on social media.
The US Polo Association said her death was devastating.
"The tragic loss of Team USPA member Lauren Biddle has shocked and saddened our polo family to the core," the association wrote in an online tribute.
"Lauren 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."
A family member took to Facebook to thank everyone for all of the messages and support people have been giving them.
"I want to thank everyone for the lovely words, thoughts and prayers. It's a trying time, but as a family we will get through this," they posted.
"It's something we never thought could happen to us, she was young, beautiful, courageous and so full of life. Always living in the present.
"Her passion for polo, or quite frankly anything horses was so inspiring. She loved to travel and experience life head-on and to the fullest - I admired that the most.
"We miss her so much."
The South Island Polo Association also said Biddle's death was horrible news and their thoughts were with her family.
"Lauren was known by many in our polo community and her fun-loving nature will be sadly missed," they wrote.
"We send our thoughts and sincere condolences to the Biddle Family."
Detective Senior Sergeant Greg Cottam said a post-mortem examination was completed today and preliminary results had been passed on to the coroner.
"As part of the post-mortem process, police and the coroner are waiting on toxicology results," he said.
"Police are still carrying out a scene examination at a Spinnaker Lane address that it is believed Lauren had been at – we expect to complete that process tomorrow."
Emergency services were initially called to the incident by a friend who was performing CPR on Biddle at Clifton Terrace.
"We have been in contact with Lauren's US-based family and have been working with the US Embassy to offer them the support they need," Cottam said.
"No further information is available at this stage. We will provide an update as soon as we are able."