By the turn of the century, the Cathedral was once again found to be inadequate in size for the burgeoning population of Auckland. Thomas Mahoney, therefore, drafted plans for the demolition of the stone church and its replacement with expanded transepts.

The completed Cathedral was reopened on 21 April 1907 by Bishop Lenihan and formally dedicated on 23 February 1908 by Cardinal Moran, Archbishop of Sydney.

This is the same Cathedral building as we know it today.