Traders in Londonderry are warning that firms will close and jobs will be lost following new restrictions in the council area.
They expressed disappointment at measures to curb the spread of the virus across the North West, which now has one of the highest infection levels in the UK.
The First and Deputy First Ministers announced the new measures on Thursday, which include limiting hospitality businesses to takeaway, delivery and outdoor dining only.
Londonderry Chamber president Redmond McFadden said: "We have to acknowledge that the consequences of these measures will mean greater pressures on our already struggling businesses and may sadly lead to business closures and job losses, particularly in the hospitality sector.
"This virus poses a real and dangerous threat to both our society and economy, and is being spread by the carelessness of individuals.
"These new restrictions need to act as a wake-up call for all of us across the North West and I am pleading with everyone in our communities to take this threat seriously."
Mr McFadden said it was an opportunity to suppress the virus again to avoid harsher lockdowns in the coming weeks and months.
"Everyone following the rules and acting responsibly will lead to a drop in cases, allow us to protect our most vulnerable, and keep our local businesses open."
Northern Ireland Hotels Federation chief executive Janice Gault questioned why a Derry-Donegal strategy was not deployed earlier.
She said: "The hope is that this localised circuit breaker will reverse the upward infection rate and help to reduce the spread of the virus.
"There are concerns that the curtailment and effective closure of a well-regulated and responsible industry may lead to an increase of social gatherings in private dwellings and other venues which are significantly more difficult to police."
Dr Tom Black, BMA Northern Ireland Council chairman, said it was unfortunate that the Executive have had to take this action but it was good to see them acting so swiftly as quick action was one of the ways to keep the virus at bay."
He continued: "At the start of the pandemic we talked about flattening the curve and I think we are now in that place again.
"We really need to slow the spread to make sure our hospitals are not overwhelmed.
"Talking to my colleagues in hospitals I can see that many of them have not recovered physically or emotionally from the first wave, and a second wave with increased hospitalisations would really cause immense strain on our already stretched system."