Franklin Zoo is closing, leaving the fate of African elephant Mila in doubt.
Jenny Chung, whose sister Dr Helen Schofield was killed by Mila in April, has told Closeup the sanctuary will close after failing to get sufficient funds to remain operating.
The zoo must find homes for about 430 animals and birds, including Mila.
"It's been a very difficult decision to close the zoo," Chung told Closeup.
The loss of Schofield's expertise was partly behind the closure.
Chung said she still hoped to send Mila overseas with the help of public donations, but would not say outright if the move was certain.
The Animal Sanctuary for unwanted animal, south of Auckland, had appealed for donations to remain open and cover the costs to send Mila to a new home in the United States.
In June, the Franklin Zoo Charitable Trust announced it needed $1.45 million to secure Mila's care or she may be put down.
The Ministry of Primary Industries had a legislative requirement for the trust to have an accredited zoo manager and elephant programme manager on staff in order for it to remain open.
Schofield was killed by Mila on April 25 when the elephant picked her up with its trunk before bringing her down and crushing her.
Schofield was preparing the ex-circus elephant, formerly known as Jumbo, to be transported to the Performing Animal Welfare Society in San Andreas.
The $1.45m needed would go towards funding an accredited zoo operator, an elephant programme manager, two more elephant keepers, a custom-built travel crate, vet care, medical testing, crate training, freight to her new sanctuary, quarantine and the final transfer to her new home.
Chung had said Mila may be euthanised if the money wasn't raised and no other facility in New Zealand could care for her.