But the government says the Treasury Board quashed the project in January 2014.
Spokeswoman Kathy Young says the library would have included documents and other materials associated with all the province's premiers.
Warren McCall, central services critic for the NDP, says drafting what he calls a "vanity project " wasted employee hours.
He also suggests the proposal was the basis for another project dubbed the Museum of Democracy.
NDP Leader Cam Broten criticized that museum project in October, saying it was a strange government priority.
The government has said if the democracy museum were to go ahead, it could be virtual and would not necessarily have a physical space.
Note to readers: This is a corrected story. An earlier version said the Treasury Board quashed the premier's library proposal in May 2013.