Deposits from Irish households stood at a record €135 billion at the end of September, according to the Central Bank.
That represented a net increase of €1 billion over the month, the figures show.
It contrasted with a decrease of €56 million in the month of August as household withdrew more cash than they deposited into accounts.
Compared to the situation at the end of September last year, total deposits were up €13.5 billion, or just over 11%.
Overnight deposits, which include current accounts, continue to be the driver of the increases in household deposits.
Households put records amounts of cash on deposit during the pandemic, despite financial institutions offering little or no return on savings to customers.
The country's two main pillar banks have started levying negative interest rates on personal banking customers with deposits in excess of €1 million.