Bombardier and Wrightbus, two of Northern Ireland's biggest companies, have closed their sites until April 20 because of the coronavirus pandemic.
Yesterday's decision at aerospace manufacturer Bombardier came a day after staff expressed concern about social distancing at work.
Some employees at the company's east Belfast site brought their concerns to management on Monday morning.
Meanwhile, Ballymena bus manufacturer Wrightbus announced that in light of Government guidance, it would temporarily close its factory to protect its workforce, their families and the local community.
This newspaper was contacted by employees from companies around Northern Ireland yesterday claiming that businesses were refusing to shut down in response to the Covid-19 pandemic.
Elsewhere, First Minister Arlene Foster stated that construction sites should remain open if builders can adhere to social distancing guidelines.
The chair of Stormont's All Party Group on Construction, SDLP MLA Patsy McGlone, called on the Government to act on the advice of the Construction Employers Federation to cease work on non-essential construction sites.
In an internal memo to staff yesterday, Michael Ryan, chief operating officer of aerostructures at Bombardier Aviation, explained that following announcements from the company on the closure of sites in Quebec and Ontario, all production would temporarily stop in Northern Ireland.
Mr Ryan said that Bombardier's decision to close would allow the company to review its factories and office areas to ensure that social distancing guidelines can be met.
"We will keep the situation under constant review, given any change in the Government's guidelines and essential business needs driven by any customer requirements," Mr Ryan explained.
"Before leaving today, please work with your local supervisor to ensure your work area is left secure, safe and tidy.
"On exiting the facility, please leave in an orderly fashion, respecting your colleagues and maintaining social distancing."
The memo also said there was a "lot of uncertainty" from the Government and Bombardier's customers and ensured employees that they would communicate with them as frequently as possible.
Following the internal memo to Bombardier's employees, the company publicly confirmed the decision to close.
"In the current unprecedented circumstances, we want to make the best decisions possible for our people, our communities, the wider Northern Ireland society and the sustainability of our business," a statement read.
"As the UK ramps up efforts to delay the spread of Covid-19, and following announcements from Bombardier Aviation on the closure of sites in Quebec and Ontario, Canada, we have made the decision to stop production temporarily at all our Northern Ireland sites until April 20.
"These measures will help us maintain as many people as possible in full-time employment.
"Critical support will be required to continue during the furlough and therefore some employees will be required to work during this time, obviously continuing to maximise working-from-home opportunities and the safest working practices."
Bombardier added that the four-week shutdown applied to all other employees and consists of a furlough of almost three weeks within the Government's job retention scheme guidelines and five days' vacation at Easter on full pay.
Wrightbus said last night that the "temporary pause in manufacturing" would commence from midnight and stay in place until April 20.
"We will keep this under review and are committed to resuming production as soon as possible," the company said.
"We understand this is a difficult time for all concerned and we are seeking guidance from the Government on the measures they will be taking to protect the UK manufacturing industry and its workforce."
Meanwhile, Sawers deli in Belfast city centre is planning to deliver as many meals as possible to its elderly customers before closing its doors this Friday.
Proprietor Kieran Sloan explained that the store was operating on reduced hours and only providing a takeaway service.