More than 200 virus clusters have been identified in nursing homes and residential institutions to date and 245 people in care homes have died, Chief Medical Officer Dr Tony Holohan said yesterday.
The overall death toll from Covid-19 in the Republic stood yesterday at 444, up by 38.
One nurse, who worked several shifts over the Easter weekend in a Dublin nursing home, said that where there was an outbreak, the staff were "overwhelmed".
The woman, who asked not to be identified, expressed concerns about the lack of oxygen supplies available to patients who have the coronavirus.
"What hurt me the most was that I only had one oxygen tank," she said.
"There were others who could have done with it but it was attached to one person.
"The HSE needs to get oxygen into all of these homes. This is a respiratory disease that affects your breathing and patients struggling with it need oxygen.
"Nobody is talking about what is happening in our nursing homes. These are our loved ones."
Oxygen supply problems have also been raised by nursing home owners in the private sector, who have reported difficulties with procurement.
However, the HSE said it was working closely with contracted suppliers of oxygen to ensure continuity of supply to all users, and there were no shortages at present.
"The focus early on was on personal protective equipment and oxygen has fallen under the radar," said Tadhg Daly, CEO of Nursing Homes Ireland.
"This is something we have raised with the department and, to be fair, they have been addressing it."
Nursing homes, including one in Dublin where at least 15 people have died, have been dealing with deaths for some time.
By April 4, when Health Minister Simon Harris announced a €72m support package for homes, at least four of its residents had already died from Covid-19.
The home had been struggling with staffing issues and PPE supply.
An expert team from the HSE has since entered the facility, where efforts are continuing to stem the infection and prevent further deaths.
While announcing the support package for nursing homes, Mr Harris warned that agency staff, who move from home to home, presented a risk of spreading the virus.
Dr Siobhan Ni Bhriain, of the HSE, said a strategy was now in place to support nursing homes, including providing more staff from the public system.
An HSE spokesperson told the Herald it was working closely with contracted suppliers of oxygen, and assurance has been provided that supply chains have been and will be maintained.
"Healthcare Organisations - CHOs - are working closely with staff in nursing homes, both HSE and private facilities and other residential care settings, to support the processing of prescription orders to ensure timely supply for relevant patients," the spokesperson said.
"There is no shortage of oxygen or oxygen concentrators for nursing homes at this time."
Health workers are to be redeployed to private nursing homes in an effort to curb the virus spread.
The Siptu union and the HSE have signed off on a deal in which staff in the public health service will put their names forward and a volunteers register will be set up.
Volunteers will come from nursing, health care assistant, cleaning, chef and catering assistant roles.
However, management at the residential homes will have to have exhausted all avenues to recruit staff before they can use the scheme.
"Our members want to help deal with the increasing clusters of the virus among the most vulnerable service users in the nursing home sector in their catchment area," said Siptu health division organiser Paul Bell.
"However, until now, there was no policy or protocol for members asked to provide assistance to private nursing homes which are not under the governance of the HSE."
Staff will remain under HSE management and will be assigned for agreed periods of time.
Mr Bell said they will also be provided with an adequate supply of PPE.
"This development arises because of challenges that have emerged in some private nursing homes to manage the Covid-19 crisis," he said.
"We will engage with the HSE and Department of Health for a critical review and analysis of this work when the crisis abates."