Children up to age 8 can then borrow as many toys or puzzles as they like for two weeks.
Toys are 50c and puzzles are free.
Woon said children went through the stages of development quickly and buying puzzles to keep up could cost parents a lot.
"If you went out and brought the puzzles, you would be spending a lot of money and they may only use them for a month, whereas the membership here you can just keep on going," she said.
The librarian of five years said the number of grandparents signing up as members had grown rapidly recently.
"People are buying a $30 voucher instead of buying a child a present at a party so they can come here - and you get so much more for your money then buying a present," she said.
Currently, 70 families were members of the library which meant 280 children had access to a large range of toys from play sets, musical instruments, costumes to outdoor bikes and coupe cars.
The committee applies for grants to buy new toys and accepts donations from the community.
Chairwoman Rowena Spoke said it was a fantastic resource that could save families a lot of money.
"We are a low-income family and we didn't have room in our house or money to keep buying new toys for my daughter, so the library has helped to save lots of money and to not waste endless amounts of plastic toys," Spoke said.
*The Whanganui Toy Library is open Thursdays 9.30am-11.30am and Saturdays 10am-12pm.