The Central Otago District Council ditched the crime and punishment approach to borrowing across its six libraries on July 1.
The number of active readers has since increased by 107%.
The fine-free shift has brought missing items back to the library, council communications officer Mary-Jo Tohill said.
"We have had reports of local patrons relieved to be able to return books that were lying around at home because they were previously ‘too scared’ to return as they had mounting fines to pay," Ms Tohill said.
The day before fines were removed on June 30, 4649 people had taken out a book at their local library in the past two years, but in the past three months there has been a book-borrowing boom.
An additional 4991 readers have borrowed an item from the period July 1 to October 31, bringing total readership numbers to 9640.
Central Otago was one of the last areas in the country to ditch late charges for adult books.
According to Fine Free Aotearoa (FFA) data, only 11 of the country’s 53 councils still have these penalties in place.
FFA data showed that by mid-2022, more than 50% of local councils had already eradicated fines.
Ms Tohill said there had been a very positive response from patrons on the decision to go fully fines-free, noting children’s books had been fine-free since 2017.
"This had a significant impact on young families who often took out many books at a time and could rack up big bills. Going fine-free for adults has been well-received, despite not having a lot of publicity," Ms Tohill said.
An extra 130 people have also joined the library since fines were removed.
However, Ms Tohill said the removal of fines did not mean no responsibility.
"Once an item is six weeks overdue it will be considered lost and customers will be billed for the replacement cost."
Fees will be waived if the book is returned in good condition.
