A new report by employers' group Ibec has shown €1.5bn in extra supports for businesses will be needed from the State over the next three years if the UK crashes out of the EU without a deal.
Ibec claims decisive intervention will be required from the Government in order to prevent job losses and business closures as a result of a hard Brexit.
The Government has signalled that it will announce a range of measures in Budget 2020 to help business that would be deployed in the event of a hard Brexit.
It has not yet said how much it is willing to commit to such schemes or from when exactly they will take effect.
But Ibec says the risk of a 'no deal' is imminent and action is required immediately to provide economic stability and protect employment.
In particular, it said pressure will come on firms from a depreciation in sterling, cancellation of investment, cash flow challenges and increased trade costs, with the rural economy facing a structural shock.
"Timing is of the essence," said Ibec Chief Economist Gerard Brady.
"Our experience from 2009 shows that it took ten months from agreement on a State Aid framework at a European level until companies could draw down supports.
"In a no-deal scenario, if supports were not available until the middle of 2020, it would be far too late to sustain enterprises and jobs in many areas."
Ibec wants the Government to set out a multi-annual funding framework of State aid for industries that will be most affected in tomorrow's Budget.
It said the assistance should be targeted not just at the agri-food sector, but also the wider domestic economy, including traditional manufacturing, retail, tourism, forestry, construction, energy, transport, utilities, and telecoms.
Specifically, it wants the Enterprise Stabilisation Fund that was available during the financial crisis to help viable companies in temporary difficulties to be reintroduced and enhanced.
A short-time work subsidy scheme is also required for two years at least, it said, to help vulnerable workers by providing a subsidy of up to 60% of their reduced net wage for up to a year.
It is also calling for an employment subsidy scheme offering up to €10,000 over two years to help maintain jobs in vulnerable firms where short-term work is not possible.
Ibec said that an acceleration in the current credit guarantee scheme's coverage of invoice discounting in small and medium sized firms where cash flow is hit by Brexit was also required.
It claimed that a new export credit insurance scheme aimed at helping businesses to diversify away from the UK is needed.
The criteria for the existing loan schemes also need to be loosened, it says.
In particular, the organisation warns rural areas are at risk because those most vulnerable to job losses already live in areas with fewer opportunities and lower incomes.
"The companies most exposed are both capital intensive and low margin," said Mr Brady.
"If firms collapse in a no-deal scenario, they will not be easily replaced."
In relation to the thorny question of State aid rules, the confederation says that in the EU, there is precedent for such temporary supports at moments of crisis.
In total, 5% of the value of current annual indigenous export sales to the UK, worth €500m, will be needed over each of the next three years.
Ibec said the cost of the measures could be partly funded by new tariffs that will have to be levied on Irish imports from the UK.