Business organisation DublinTown has said that footfall in Dublin city centre between Monday March 16 and Sunday March 22 slumped by 65.8%.
This means that about 200,000 less people are visiting the city centre every day.
DublinTown said the downward trend during the week became more evident as businesses chose to shut their doors. It noted that the decline on Monday March 16 was 37.5% but by Saturday it was 77%.
Footfall on St Patrick's Day 2020 was down 71.7% on the level recorded on St Patrick's Day 2019, it added. St Patrick's Day normally marks the start of the tourism season here.
DublinTown's data showed that streets with the high concentration of hospitality businesses were most impacted.
South William Street recorded a reduction of 85% while Grafton Street saw a reduction of 75% in its footfall.
Many of the city's businesses have chosen to close their doors in the interests of the health and welfare of both customers and staff, but others providing essential retail and hot prepared meals are continuing to meet customer needs while exercising responsible social distancing.
However, the majority of DublinTown's 35,000 retail and hospitality workers have already been temporarily laid off or are facing a very uncertain future.
DublinTown's CEO Richard Guiney said the outbreak of Covid-19 is an unprecedented event, starkly illustrated by the dramatic decline in city centre footfall.
He said that many of DublinTown's members are small, family owned independent retailers, restaurants and bars, adding that their ability to get through this is dependent on their cash reserves and personal savings.
But he cautioned that few have sufficient reserves to stay afloat for the prolonged period of several months that this crisis may last for.
"The current emergency is first and foremost a health crisis and the preserving life has to take precedence over all other considerations. However, we must also do everything in our power to ensure that the economy is ready to rebound rapidly once it is safe to do so," Mr Guiney said.
"Central to this is assisting employers to retain their skilled and talented workforce. This will require innovative schemes similar to some of those developed in other jurisdictions where employers and the state combine to provide a living wage for those forced out of work," he said.
Mr Guiney noted that many Irish retailers have developed their online services, while restaurants are engaging in takeaway and delivery services.
"Traders have noted their appreciation of members of the public buying vouchers from them. Such support from the public in these very difficult times is greatly appreciated by all concerned," he said.
"We are in this together and can emerge successfully where we continue to have a collective effort," he added.