The government set aside 1.25 billion euros ($1.3 billion) to provide businesses such as hotels, shops and restaurants with 40% of the increase in gas or electricity bills up to 10,000 euros per month if those costs rose by over 50% year-on-year.
However, just 26.1 million euros worth of claims have been paid out since the six-month scheme opened in late November.
"It's clearly not working in the way that we thought it would and that's why we are reviewing it now in a serious way," Coveney told a parliamentary committee late on Thursday.
"There are just under 23,000 companies that have registered for this. We thought the figure would be 10 times that... We are actively working to understand why."
Coveney said issues that may have led to the low uptake include the fact that many firms are still in contract with energy suppliers and may not yet qualify, while some hotels and restaurants use heating oil, which is not part of the scheme.
A 122-page set of guidelines on how to apply may also have proven "intimidating" for smaller businesses that may have felt they would need to hire an accountant to fill in the paperwork.
Coveney said officials were looking at how to make the process easier after extending the application deadline last month and whether the law underpinning the scheme needs to be amended to ease the criteria.
He added that a separate 200 million euro scheme introduced at the same time to offer larger energy users up to 2 million euros each in grant aid had so far paid out just 3.9 million euros to 14 companies.
($1 = 0.9348 euros)
(Reporting by Padraic Halpin; Editing by Andrew Cawthorne)
