Durham University added to its art collection as part of a £60m development, which opened last year.
But the public sector workers´ union, Unison, says the collection is too expensive and added that the expense could not be justified at a time of austerity.
The university defended the move, saying it was a "custodian" of fine treasures and offered free tours.
John McDade from Unison said a survey by the union had found 555 workers at the university were paid less than the living wage (currently £7.45 an hour).
"We are not saying art is not important, but it is about priorities," he said.
Last year thieves broke into the university´s Oriental Museum and stole Chinese items worth more than £2m.