Cork City Library on Grand Parade had to close on Saturday after a banner was placed over the front by protestors.
Individuals who were opposed to LGBTQ+ materials caused the library to be closed for public safety.
Separately, staff at Ballyphehane Library had to barricade themselves inside following a protest by the same group.
Lord Mayor of Cork, Kieran McCarthy, is concerned by the actions of those protesting.
"This book isn't on prominent display.
"There are procedures in place for people to complain about certain books, and this isn't the first time that has had a discussion on whether books should be banned or not.
"For me, it's about the safety of Cork City Council staff and the general public."
