"Unfortunately we are in crisis and this friendly dinosaur faces extinction," Jordan wrote on the fundraising website Givealittle.
Although he worked virtually seven days a week, Jordan said he didn't own properties or "bankable assets".
"The business has been a labour of love which pays our wages and continues to give a great many people of all ages pleasure, but there are no gold bars buried in the garden (we've looked)," Jordan said.
He wants Kiwis to donate money to help buy the Onehunga site, which he describes as "a several storey nineteenth century chaotic shambles of a timber building with well-worn wooden stairs and original wallpaper still hanging (just) from the walls".
"It is both a cultural icon and an economic anachronism with a unique bookish atmosphere available to all incomes and tastes," he said.
"Many thousands of customers from around the world have visited as children, supplied themselves as students, and now bring their children to experience the piles of tumbling books and half-hidden treasures. Hundreds more people have worked short or long-term with us over the last 34 years and helped shape the shop as it now is," Jordan said.
Jordan, who also runs a sister Hard to Find bookstore in Dunedin, hopes that Kiwis will donate enough to either buy the building outright "and restore it to its glory" or put up "a viable deposit".
While the public have donated more than $5000 to the cause, the fundraising campaign was still a long way off from the building's estimated value of $830,000.
Hard to Find's Facebook post asking for donations has already been shared hundreds of times since the fundraising drive began.
"I'll definitely add to the cause when I'm able. This book shop is just a wonderful place to mosey round in and has saved me hundreds if not thousands in text books. You guys are amazing!," Bayley Meyer wrote.
Barbara Pratt said: "Oh what a sad tale, the very idea of your shop sends my senses tingling as an avid reader and at the same time makes me sad. I have always loved delving into hidden away shops and could spend hours in them."
Others said they could remember when the book store was a local fruit and vege shop.
"The building is an Onehunga icon. Good luck with your endeavours. I'd hate to see the building gone," said Judith Hayes.