"At Whanganui District Library we're committed to getting the books to where the people are."
The new vans are substantially more nimble than the bus, meaning they can travel to areas such as the Whanganui River Road, as well as retirement complexes and outreach events.
Gray said the vans are more practical for library staff.
"Switching to vans also takes the pressure off us in terms of staffing as the vans can be driven by any holder of a Class 1 licence, unlike the bus which could only be driven by our two librarians with Class 2 licences.
"This means the vans will be on the road for more hours each week, making more stops than was possible with the bus."
The vans are being wrapped in an exterior design, with the adult van named Tahi emblazoned with a nostalgic nod to the library's history - a picture of former city librarian Miss Blackett and her team from the 1930s.
"The picture sums up our history as an organisation and the power of libraries, particularly for women at the time."
The children's van, dubbed Rua, will be covered with themes of literary heroism for children, from books like Pippi Longstocking, Captain Underpants, The Famous Five and Peter Pan.
"These are titles kids love and continue to love, and we always want to encourage that excitement for reading."
Gray said the overall cost of the new vans and a full refit fell just below the $300,000 budget and thanked the Lion Foundation and the Four Regions Trust for their support of the project. The cost of replacing the mobile library bus would have been close to $600,000.
The vans will be launched at 2pm on Friday, October 23, at the Davis Library. All are welcome to attend.