A total of 19 building sites in Cork were closed for a period in recent weeks by the Health and Safety Authority (HSA) in what it said was a "crackdown" on unsafe working.
Another workplace was also closed and seven companies were fined during inspections over a four-week period announced last month.
The inspections were organised following the deaths of four people in workplace accidents in Cork in January, one more than the total for the county last year.
Two men were killed at Tivoli docks in accidents involving trucks.
Another man died when he fell off scaffolding on a building site at Blackrock in Cork city, and a woman died in a farm accident at Cloyne, east Cork.
Since the inspection programme was announced on February 9th, HSA staff have inspected 433 workplaces in Cork. Inspectors issued 20 prohibition notices, 12 improvements notices and seven fines.
A prohibition notice, directing that activities must cease until matters are rectified, is issued when an inspector concludes that workers are at risk of serious injury.
All but one of the 20 prohibition notices issued related to building sites. The seven fines issued all related to the transport of dangerous goods by road.
The initial aim of the authority was to carry out 350 inspections during the four-week period.
Ten inspectors targeted companies in the construction, quarrying, agriculture, transport and manufacturing sectors in Cork.
HSA inspector Mark Rowlands said the authority was determined to take appropriate enforcement action where it found breaches of legislation.
"It is not acceptable that people lose their lives or are injured due to poor safety standards in work. Our programme seeks to ensure compliance with the law, and we will continue to make our inspectors available to advise employers regarding their duties."
Ultimately, he said, compliance with health and safety laws was a matter for each employer.
The number of people killed in work-related accidents in the State last year was 47, compared to 65 in 2003 and 61 in 2002. This was the lowest number of deaths since the HSA was established in 1989.
Nevertheless, announcing the Cork safety campaign last month, HSA chief executive Tom Beegan said the rate of workplace fatalities remained unacceptable.
