The National Treasury Management Agency has raised €3.5 billion through the sale of a new 20-year bond.
The bond, which matures in April 2041, was sold at an interest rate of 0.585%.
The NTMA said it received orders worth more than €35 billion as part of the sales process.
It brings to €10.5 billion the amount raised by the agency so far this year, more than half of which came through the sale of a 10-year bond in January.
The NTMA plans to borrow €16-20 billion in 2021 to fund a huge increase in government spending to keep businesses and employees afloat during the Covid-19 pandemic.
This will lead to a budget deficit of 4.7% of gross domestic product (GDP) this year, the Department of Finance forecast yesterday.
"Today's transaction underlines the continued strong demand from a broad investor base for Irish sovereign debt and means that, four months into 2021, we have raised close to 60% of the mid-point of our target funding range," said NTMA director of funding and debt management Frank O'Connor.
"Coupled with our strong cash balances, this gives us significant flexibility in meeting our borrowing requirements over the remainder of 2021."
Today's issue is the longest dated sale Ireland has placed via a syndicate of banks in almost two years.
Long-dated issuance has resurfaced after dying down in February when the bond sell-off driven by growth and inflation expectations hit longer-dated bonds particularly hard, as they are more sensitive to a rise in underlying rates. Bond yields move inversely with prices.
"Today's 20-year transaction reaffirms our approach to issue longer dated bonds when demand allows it," said Mr O'Connor. "The low interest rate environment over recent years has created opportunities to lock in the benefits of low rates for the longer term and gives us greater certainty over future debt servicing costs."
The NTMA had mandated Barclays, BNP Paribas, Cantor Fitzgerald Ireland, Danske Bank, JP Morgan and Nomura as joint lead managers for the sale.
It was the first syndicated deal since the agency dropped Ireland's largest stockbroker, Davy Stockbrokers, as a primary dealer in Government bonds following a record Central Bank fine of €4.1m for breaching market rules.
Earlier, the agency also completed an auction of Irish Treasury Bills, selling the target amount of €750m.
Total bids received amounted to €1.7 billion, which was 2.3 times the amount on offer.
The Treasury Bills, which have a maturity of six months, were sold at a yield of -0.602%, the NTMA said.