Chambers Ireland has called on the Government to extend the wage subsidy scheme for some sectors and introduce a 12 month waiver on commercial rates in the July Stimulus, which is due to be published next week.
The organisation represents 40 Chambers and more than 8,000 businesses around the country.
It said the package of supports will be "the last chance" to ensure that vulnerable businesses survive.
It has called for more grant aid to ensure that businesses can tackle debt and outstanding invoices.
"The introduction of the 'Restart Grant' was a welcome first step in supporting business to re-open, but ultimately did not go far enough," Ian Talbot, chief executive of Chambers Ireland, said.
"Without a significant intervention from the State, the debt burden will become insurmountable for many, with closures and job losses inevitably following," he warned.
The call comes as the Government introduced legislation for a Credit Guarantee Scheme for businesses with fewer than 500 employees.
The €2 billion scheme aims to provide low cost loans to companies via the main banks, with an 80% guarantee from the state.
Mr Talbot said, while the Credit Guarantee Scheme was welcome, the issue for most companies varied from working capital to reopening costs and bad debts arising from the pre-Covid era.
"It's not the sort of thing you'd look to borrow for. This is why we're looking to grant aid," he said.
Mr Talbot acknowledged that businesses had gone into this crisis in a much healthier financial position than the downturn over a decade ago.
While they were generally in a position to take on debt, he said it wasn't suitable for the situation that they had found themselves in of late.
"The issue is around fixed overheads that firms haven't been able to cut. Bad debt is a very circular thing. If one company can't pay another, that sparks off the next company. If we can start the cycle of debt repayment, that would be very helpful."
As well as an extension to the Temporary Wage Subsidy Scheme for vulnerable companies, Chambers Ireland is calling on the Government to allow impacted firms to hire new staff under the TWSS.
Mr Talbot said it was difficult to say at this stage how long an extension of the TWSS to vulnerable companies would be required for, but he mentioned a time frame of 12 months.
Chambers Ireland also wants the Government to commit to making up the shortfall in Local Authority funding arising from its proposal to extend the commercial rates waiver for a year.
"If Government does not continue to intervene in a meaningful way, with a package totalling billions of euro, then it is quite probable that huge numbers of jobs and job creators will be lost to the economy," Mr Talbot said.
"If the State intervenes, we have a much better chance of protecting local economies all over the country. Without such an intervention, the economic outlook is bleak," he concluded.