An average of one in every 25 people who borrow library books in recent years does not return them on time.
But the National Library Board (NLB) has, over the last two years, observed a 7.8 per cent drop in the number of patrons who returned books after the due date. On average, those who return their books late do so within 14 days last year, down from 23 days in 2014.
Ms Catherine Lau, assistant chief executive of public library services at NLB, said: "Patrons are holding on less to library books and returning them earlier once the books become overdue.
"Everyone can play their part and stay fines-free, so that others can also enjoy these library materials."
NLB was responding to queries from The Straits Times after a writer to the ST Forum complained last Saturday that her library fines cost more than the books borrowed, giving her and her children a "phobia of borrowing books from public libraries".
This swiftly sparked a public backlash. Many said returning library books late deprived others of the chance to read those books, while some criticised the writer for not setting a good example for her children.
The writer's daughter had borrowed two books from Toa Payoh Public Library last December, but forgot to return them.
She received a reminder to do so this month, and returned the books. She also wrote in asking for the fines of $31.42 to be waived, as "the late return was not intentional and this was the first time it had happened".
Despite this, she was required to pay $25 in library fines, more than the total cost of the two books, which was about $16.
Ms Lau said NLB is mindful that patrons "have busy schedules", and has services to encourage them to return their books on time, such as a free e-mail reminder service.
Those who wish to enjoy their borrowed books or music scores beyond the 21-day loan period can get a one-time loan renewal of another 21 days for free, she added.
Library users said the move by the library in this case is fair.
Housewife Jolyn Ho, 43, who has two school-going children, said imposing fines on late book returns goes towards cultivating good values in her kids from a young age.
"It can itself be a lesson in responsibility for young children," she added. "They learn to take care of the books and return them on time, so others can read them too."
Sales manager Jonathan Fong, 30, said: "Sometimes, it is easy to forget the deadline. But I don't think most people will chalk up huge fines, unless they return (the books) a few months later."
Several patrons, such as housewife Lydia Tan, 38, agreed that fines serve as a good reminder for borrowers to return their books promptly.
"The books are not theirs to keep," said Mrs Tan, who has a six- year-old son.
"Most people borrow books because they want to save money. Having fines for late book returns will hit them where it hurts."