The majority of hospitality businesses have failed last-minute inspections for reopening as the Covid-19 lockdown eases, an industry body has said.
Outdoor restaurants, bars and pubs in Northern Ireland are set to reopen on Friday under the new regulations.
But Hospitality Ulster said there was "chaos" over the implementation of the rules for the sector.
It said many venues had been told their outdoor seating areas did not adhere to guidelines from the Stormont executive.
'No more than 50% enclosed'
The Executive Office said there had been "no change to the definition of indoor and outdoor areas which applied last year".
The Department of Health said the general rule of thumb was that outdoor premises should not be more than 50% enclosed.
The legislation states that a premises is enclosed if it has a ceiling or roof or is substantially enclosed if it has a ceiling or roof but there is "an opening in the walls".
Councils are responsible for conducting the inspections of hospitality businesses in their area and enforcing the regulations in relation to them.
Belfast City Council said that while the definition of an outdoor area had not changed since last summer, legislation about "when and how hospitality can operate has been subject to significant and constant" change.
"The key difference is that the focus of the previous regulations was on whether hospitality could be open at all and if so whether they could serve food and drink on their premises.
"Therefore we were not required to consider if any outdoor hospitality space met the outdoors criteria.
"In the latest regulations the focus now is on allowing hospitality to operate outdoors."
The council said it tried to advocate a "different approach" to the new regulations but that it was ultimately the decision of the Executive Office.
'Could have been avoided'
Hospitality Ulster chief executive Colin Neill said the situation was a "direct slap in the face" for the industry on the eve of reopening.
The interpretation of regulations was "far too stringent", he said, and he called for a "common sense" approach.
"It's chaos right across the province as a result of the Executive Office refusing to engage for months," he said.
"This could have been avoided if rules had been communicated earlier - there is no excuse for no engagement."
The Beannchor Group has said 10 of its 12 venues faced significant reductions to the space they could use as a result of the inspections.
The venues will open on Friday but not to the capacity the company had intended.
It owns Belfast venues such as the Dirty Onion, the National, and the Ulster Sports Club.
Council inspectors say they are working with businesses to help them to comply with the rules.
But the failed inspections have come as a shock to business owners who thought their premises were compliant.
Many of them had put a lot of money into renovating their premises to make them Covid-safe.
They are now trying to make last-minute adaptations in order to be able to reopen on Friday.
Connell Wolsey, a director of the group, said the inspection failures had "hit us substantially".
"In the last lockdown we were inspected 50 times and we passed every single time," he said.
"Even the chief medical officer and the chief constable were happy with the levels we had gone to."
'Nonsensical reading of the law'
He said that although the regulations for the sector had not changed, it appeared that Belfast City Council and the Stormont executive had "decided to enforce them in a different way".
His group spent £40,000 to install a retractable awning at one venue before opening on Friday only to be told it could not be used as it created an enclosed space.
"They're treating a picnic parasol as a roof - it's just a nonsensical reading of the law," he said.
He said that without the use of parasols, many hospitality businesses "will have to base their opening hours on the weather forecast".
John Leighton of Bennigans Bar in Londonderry said he has had to take the difficult decision not to reopen on Friday.
He said there were "too many grey areas" when it came to how the 50% of enclosed space was determined.
"It became clear in conversation with the licensing officer that it was just about impossible for us to reopen," he said.
"We were so excited, had done all the preparations but I am not prepared to risk a fine or losing my licence."
He said the bar would instead reopen on 24 May.
Monika Rawson was told on Thursday that she could fully reopen her restaurant in east Belfast because part of her outdoor terrace is covered by a roof.
She said it was "hard to keep going" while the restaurant was closed and the business had already struggled to survive during lockdown.
The resulting stress has caused her to lose her hair, she said.
"I'm very upset - when I think about it I feel like crying."