Businesses shouldn't reopen until they can comply with new health and safety rules, the Health and Safety Authority has warned.
Dr Sharon McGuinness said that firms should be assured they can protect their workers and customers before they reopen.
The HSA chief executive said the new protocol set out the different measures that employers and staff must put in place before they can return to work.
The Government's Return to Work safety protocol includes regulations for social distancing, hand hygiene, first aid and mental health support for returning workers.
Dr McGuinness said the measures have been agreed with trade unions, the Construction Industry Federation (CIF) and other bodies.
"A decision has been taken in terms of the roadmap which is applying a risk-based approach as to what opens and when," Dr McGuinness added.
"It also enables the workplace to apply a risk-based health and safety approach and bringing those two together in the protocol to enable most workplaces to determine how best to return to work.
"Obviously they shouldn't reopen until such time as they are assured that they can protect their workers, but also protect any customers and clients that might come too.
"Once reopened and once opened then all workplaces will be required to comply with the protocol and the employers need to assess the protocol in advance of that reopening and make sure that they have the steps in place with that."
Dr McGuinness said the HSA acknowledges it will be challenging for businesses to adhere to all the new measures.
But she also warned that the HSA has the power to close workplaces which fail to comply with the new measures.
"The protocol not only covers occupational health and safety, but it covers public health, so there's a whole range of other engagements and measures that are there," she added.
The National Public Health Emergency Team (NPHET) will meet today to discuss the restrictions in place to prevent the spread of Covid-19.
The expert committee, which is chaired by Dr Tony Holohan, meets twice a week and advises the Government on Covid-19.
Meanwhile, an Oireachtas committee examining the Government's response to Covid-19 will sit for the first time later today.
The new Oireachtas Covid-19 committee will look at how authorities and agencies have responded to the pandemic and take evidence on the State's response.
The special 19-member Oireachtas committee, which was set up last week, will consider the election of a chairperson, preliminary discussion on the development of a work programme for the committee and a date for the next meeting.
