This summer the library offered the Great Te Aka Mauri Reading Challenge from mid-December to February 3.
Children up to 18 could cross off a box on the challenge sheet for every 15 minutes they read. Those that reached a total of eight hours reading could return their sheet and be in the draw to win a share of $1000 worth of vouchers.
"With a week to go until activity sheets are due to be returned we're already delighted to see some children way exceeding the target, having read their way around Lake Rotorua multiple times," Gilbert said.
Rotorua Principals' Association president and Mokoia Intermediate principal Rawiri Wihapi said he had noticed the slide and there was always a time after the holiday "where students will slip or forget some of their learning".
He said in his experience a return to school routine helped set children back on track.
New Zealand Literacy Association president Joy Hawke said the ability to read was a basic human right.
She worked with the International Literacy Association and said its recent campaign Children's Rights to Read highlighted how an ability to read allowed people to participate in society.
"These are really important statements to hold dear in a community and school," Hawke said.
She said it was important to not make reading a chore, and instead said it was about making it interesting and relevant to individual children.
"It's about knowing your kids, knowing their families, and knowing the texts that would engage the kids."
But as the summer holidays draw to a close, children who have not maintained a level of reading during summer are not a lost cause.
Hawke said it was important to not have a doomsday approach to lost progress and, with effort, it could be caught up.
Like sport or an instrument - practice makes perfect.
"It'd be a very depressing place if we thought people couldn't catch up."