Customers trying to withdraw cash from the main Post office in Kilkenny city were turned away at the weekend.
An Post says an unusually heavy demand for cash at the High Street branch meant staff were unable to make cash payouts to a number of customers.
Its understood that some of the customers were trying to draw their pensions on Saturday but were turned away.
An Post says an extra supply of cash was made available later in the day but they were forced to postpone a number of payments until the office re-opened this morning.
They have apologised to any customers who were inconvenienced.
