Hospital trust manager Jordana Whyte said without the $100,000 anonymous memorial gift the hospital recently received, the board had feared the hospital would have been forced to shut its doors in "about 18 months".
Donations were down $160,000 on what had been anticipated and the hospital for native species was spending its reserves to stay open.
Miss Whyte said it had been hard to express to the donating family the gratitude felt by the trust.
But the memorial gift "made a lot of us quite emotional when we received it".
"This gift is massive.
"I genuinely wonder if these folks really understand that it is a lifeline for us.
"I don’t know if they really, truly understand the impact.
"And I tried to express that to them, but I’m not sure, because they didn’t want any kind of a fuss made."
They asked for "no fuss, no acknowledgement, nothing official — we of course passed our effusive thanks along to them".
Any time somebody left money in their will for the wildlife hospital, it was emotional.
However, the wildlife hospital was in "a really scary" financial state.
"This doesn’t substantially change our position. We still need to go out and fundraise, but it just gives us a little bit of a sense of relief.
"The whole tone of our board meetings has changed quite a lot in the last four months, I would say, to be ‘not quite panic stations’, but we are to the point where — because we are living off our reserves — we were crunching the numbers and saying we have about 18 months left before we have to shut our doors."
The trust had been deeply concerned that there was "maybe two hoiho seasons left in us", she said.
Last year, the hospital’s wildlife veterinary team treated 644 patients, including 192 hoiho (yellow-eyed penguins) and 165 hoiho chicks.
