Around four in ten firms surveyed by the Central Bank say they have unpaid invoices.
The outstanding amounts equate to about 20% of 2019 revenue, according to the regulator, which may result in increased pressure to cash flow.
As many as 42% of firms said they had changed or deferred payments to manage cash flow.
The figure increased to 91% in the accommodation and food sector.
The survey results come as the government prepares to unveil its July stimulus, which, it's understood, will contain a range of measures targetted at small and medium sized enterprises in the form of low cost loans and grants.
The Central Bank of Ireland's SME Market Report also suggests that around a quarter of firms had ceased trading temporarily or permanently in April, but this declined to 11% by the end of May, reflecting the gradual reopening of the economy.
The main banks reported that SME credit demand increased in the second three months of the year and is expected to increase slightly in the third quarter.
Company credit enquiries spiked in April for overdrafts as other products declined.
"The spike in overdrafts was likely as a precautionary measure to ensure the availability of working capital and declined thereafter. In contrast, enquiries for other products declined in April and gradually recovered through to the end of June," the report said.
The banks said lending standards had tightened in the first half of the year and are expected to tighten further in the months ahead, by not by much.
As of May, only 6% of SMEs reported that access to finance had declined.
That was down 9 percentage points from March and April.
Around seven in ten SMEs reported no changes in access to finance, according to the Central Bank.
Legislation on a Credit Guarantee Scheme has been published by the government.
Expected to be operational by the autumn, the scheme will make overdrafts, term loans and working capital available to businesses with up to 500 employees that have been severely hit by the Covid-19 pandemic.
It's intended the scheme will have a risk share of 80% for the state with the banks shouldering the remaining 20%.
Responding to today's report, the organisation representing brokers said the interest rates being charged to SMEs under various state schemes were too high given the current circumstances.
Brokers Ireland said rates of between 4% and 5.5% being charged under the Covid-19 Business Loan scheme and the Working Capital scheme were 'unrealistically high.'
"For far too long the vital SME sector has got little more than lip service from policymakers, despite employing 65% of employees," Rachel McGovern, Director of Financial Services at Brokers Ireland said.
"The Government has to do much better than what is currently available and offer loans at rates of interest closer to zero. Anything else would see lenders profiteering on the backs of struggling SMEs," she added.