The Irish Postmasters' Union (IPU) has said the country's post office network urgently needs an investment of €15 million per year over five years to secure the future of the service.
The figures are contained in a new report by Grant Thornton for the IPU.
Without adequate funding, the union has claimed that the future is bleak, and the prospect of rapid, unrestrained closures is an immediate threat.
The Grant Thornton research places a figure of between €344 million and €776 million on the annual social and economic value of the post office network to communities across Ireland.
With the current Government funding arrangement due to expire at the end of 2025, postmasters are now calling for immediate clarity from the Government to ensure the continued sustainability of the network.
"As banks continue to close branches and Ireland transitions to a more digitally-focused economy, post offices have become critical for financial inclusion and cash accessibility, particularly for vulnerable citizens and rural communities," the IPU said.
The union said that rising cost-of-living pressures, inflation, wage increases, and compliance costs that have severely impacted postmasters’ incomes, but post offices remain ineligible for many available business supports.

They are also unable to increase their prices due to their contract requirements with An Post.
"The Government can secure the future of Ireland’s post office network with a strategic investment of less than €3 per citizen per year - less than the price of a cup of coffee," said IPU President Seán Martin.
"We’re asking for a clear, long-term commitment, not just short-term support," Mr Martin said.
"This investment will not only protect essential community services but will also enable postmasters to take on additional roles, such as increased banking services, public identity verification, support for Government energy-efficiency schemes, and processing of public forms like passport applications and voter registration, helping relieve pressure on frontline public services," he added.
A spokesperson for the Department of the Environment, Climate and Communications said the Government is committed to supporting Ireland’s post office network.
"The Programme for Government states that the Government will continue to provide the nationwide network of post offices with funding to ensure their sustainability and enhance the value they bring to local communities," the spokesperson said.
"The relevant officials in the Department are working to deliver on this and are engaging with relevant stakeholders in relation to the funding."
"Additionally, the Department is working with Government colleagues to secure future funding in line with the Programme for Government," the spokesperson added.
An Post is fully self-funded and commercially independent, but the post office network is mainly composed of independent individual businesses run by postmasters who provide services under licence from An Post.
An Post said it supports the efforts of the IPU to have the Government extend and increase direct funding for postmasters to €15 million per year and put that on a permanent footing.
"The funding protects the post office network and ensures that citizens and businesses nationwide can continue to access trusted, practical and ever-expanding services in their own communities," an An Post spokesperson said.
'It's becoming increasingly difficult’ - Galway postmistress
Postmistress Imelda Burke in Ahascragh, Co Galway said it is becoming increasingly difficult for post offices like hers to operate.
Her family has run the post office in the rural village near Ballinasloe for nearly 100 years and Ms Burke has been Postmistress there for the last 38 years.
Speaking on RTÉ’s News at One, she said: "Our wages are going down, I think 20% since 2020 and although we have some Government funding, we're at a loss to know how we can make this up.
"The prices are rising, ESB, rates and various things and it's just we're struggling, every post office is.

"We're vital for the economy of the locality. Whenever I'm busy, the local butcher is busy, the hardware is busy, the local shop is busy.
"When I'm quiet, they're quiet, so it has a knock-on effect and there isn't a price that you can put on that."
According to Ms Burke, local post offices are far more than a business to the communities they serve.
"We had an incident there recently where a customer came to the counter and I knew when he signed his signature, there was something amiss.
"Luckily, we called an ambulance and that gentleman is fine, but had that gentleman gone home on his own, God knows what would have happened.
"I mean, you can't put a price on things like that. You're keeping an eye on the elderly people. They're coming in, they trust you and it is a pleasure to serve them.
"But unless we have enough funding to keep going, sadly, there will be a lot of post offices that will close the doors," she said.
She feels that the current economic conditions for those trying to operate a small business do not allow rural post offices like hers to expand or develop their services.
"It's actually very bleak. I would love to be able to say, because I'm busy, I would love to say well, right, I'll have a full-time staff here, but I simply can't afford it.
"You know it is bleak and it is an awful pity, because every community deserves to keep their post office and to keep local money local," Ms Burke added.
Additional reporting Sally-Ann Barrett