The Health and Safety Executive has fielded complaints about approximately 480 firms during the Covid-19 lockdown.
The body, which was criticised for not inspecting sites in response to social-distancing concerns in the workplace, said such visits have now begun.
The figures are a measure of the challenge faced by employers and employees as society contemplates a widespread return to work.
The complaints cover the period between 16 March and 4 May.
The Health and Safety Executive (HSENI) said while the volume of calls is no longer what it was, it is "still high and remains constant".
The issue has been given fresh impetus by the death of a Moy Park worker who contracted the virus, and evidence of disease outbreaks amongst workers in a number of meat plants.
All the companies said they have put stringent protection measures in place and are complying with official guidance.
Until 4 May any Covid-related complaints to HSENI had been dealt with "remotely".
It is believed that entailed measures including providing advice over the phone and seeking evidence of compliance with social distancing guidelines from pictures emailed by the firms involved.
But since 4 May, HSENI has been carrying unannounced site visits.
It did seven in that first week and has completed a further 29 this week, with a further seven agri-food premises to be visited by this weekend.
A protest was recently held at the Linden Foods plant in Dungannon by workers concerned for their safety.
The focus of inspections so far has been premises at which there were multiple complaints, including some food production sites.
HSENI is the lead agency for workplace safety and has responsibility for a range of workplaces such as factories and building sites.
It shares the role with 11 local councils who look after things such as shops and offices.
One of the issues facing the Health and Safety Executive is its capacity to deal with a large volume of complaints.
It has 40 inspectors, of whom 28 are able to go out on site visits.
Chief Executive Robert Kidd told an assembly committee recently that in seven weeks it had fielded 991 complaints, of which it had had to address two-thirds, passing the rest to councils.
He said his staff had worked "tirelessly" to mitigate risk in businesses which had kept working during the lockdown.
He said this was particularly the case in food production where "without sensible interpretation it could have meant the closure of essential food production in Northern Ireland, which was a very real risk in the early days"