One of the functions of the Central Bank (now called the Central Bank and Financial Services Authority of Ireland) is to act as a banker to the government - Leaving Cert Economics - Question 7 - 2006

The function of acting as a banker to the government means that the Central Bank is responsible for managing the government's financial transactions. All government revenues are paid into the Central Bank, which ensures secure handling of funds. Additionally, any payments made by the government are processed through the Central Bank, taking funds out from the government's account held there. This effectively positions the Central Bank as the main financial agent for the government, responsible for various banking operations.