Gas Networks Ireland has agreed a new €100m financing facility with the European Investment Bank.
The company said the investment will further modernise and extend the country's gas network, including the completion of the Scotland-Ireland interconnector project.
The upgraded infrastructure will also facilitate gas innovation projects such as renewable gas, which Gas Network Ireland said will play a role in decarbonising the Irish economy.
Natural gas provides over a third of the country's energy requirements and helps to generate over 50% of the country's electricity.
As natural gas is the cleanest fossil fuel, it is the most efficient accompaniment to intermittent renewables such as wind and solar.
Gas Networks Ireland's Managing Director Denis O'Sullivan said the new funding is a further endorsement of the company's strategy to provide Ireland with a secure and competitive energy supply while also playing a major role in decarbonising the economy.
"This investment in Ireland's gas network will allow us to ensure that Ireland continues to enjoy a modern and safe energy supply for decades into the future," Mr O'Sullivan added.
"The EU Bank has a strong track record of supporting energy investment across Ireland. New investment by Gas Networks Ireland, supported by the €100m of new financing, will strengthen security of energy supply to customers across the country and ensure an alternative to oil and coal," commented the European Investment Bank's President Werner Hoyer.