Mrs Murdoch said fixing the hall's roof would also ensure the longevity of the significant, 60-year-old painted mural, which stands as a feature in the hall's foyer.
The mural was designed by New Zealand war artist Peter McIntyre in 1952 and honours all branches of the armed forces on sea, land and air. It underwent conservation work in 1993, when the library was redeveloped, and again earlier this year.
"It is programmed for restoration work every few years now. What we are also doing is installing a curtain on the window facing the mural, to protect it from the sun's UV rays and it will also lower the temperature inside the hall."