The power problems the country was experiencing were unacceptable, especially given the recent astronomical increases in the utility tariffs, the Malta Hotels and Restaurants Association said.
In a statement it said this was the second time in 11 days that the country plunged into pitch darkness for hours on end.
"The economic damage due to loss of business, disruption and inconvenience to all, and also the bad impression we give to our visitors, is now too significant to ignore. In both instances the supply was off for hours during peak business time."
It said the situation was unacceptable in normal times but became even more so given the recent astronomical increases in the electricity rates.
"In any industry or service when one pays top dollar one expects top service, which is far from what Enemalta is delivering at present.
It was also unacceptable that nobody seemed to be assuming responsibility and there was no clear explanation about the cause of the problem.
"We have neither heard if similar situations are likely to persist.
"The fact that we are experiencing such problems during this time of the year, when the demand for power supply is considerably less than that during the high season, does not augur well."
The MHRA asked what would happen in a few weeks when temperatures will be higher and air conditioners will be switched on.
"In this day and age, industries expect to be given an assurance and peace of mind that that they will have a consistent supply of electricity.
"The time has now come for Enemalta to assume full responsibility for the damage caused, as Industry and indeed all consumers have a right to know what is happening and who is responsible for this deplorable state of affairs.
"At a time when the tourism industry and others are striving to regain business, we cannot accept that we are hindered by a lack of the most basic of service."
The MHRA said it was aware of the government's planned investment in a new power plant, but it was only reasonable to expect that until then, measures were put in place to guarantee an uninterrupted power supply, as otherwise the entire economy, not just tourism would pay a very high price.