A golf society who visited a hotel in Offaly with a confirmed virus cluster said 20 people from their group tested positive for Covid-19.
It comes after the Bridge House Hotel in Tullamore confirmed that it has been notified of a cluster in a group of guests who stayed in the hotel last week.
In a statement to RTÉ's Liveline, a spokesman for 'Entertainers Golf Society’ said they adhered at all times to HSE guidelines on Covid-19 while visiting the hotel.
It said: "We have been tested by HSE and up to 20 of our group, unfortunately tested positive for this awful illness. We want to assure Liveline listeners that we adhered at all times to HSE guidelines on Covid-19."
The group also said a member of their group died suddenly on the trip.
A medical examination discovered that she had Covid-19, however it was not related to her death.
The society said: "When we were informed, we all immediately self-isolated and gave full information to the HSE about where we visited, including the name of the restaurant and pub."
In a statement this evening, the HSE said: "If you were in the Bridge House Hotel in Tullamore from the 6th to the 17th of September, please be highly alert to symptoms of Covid-19.
"We are now asking two things of you: 1. If you develop symptoms please contact your GP and explain you are linked to the hotel so that testing can be arranged.
"2. Please reduce the number of people you are in close contact with."
Earlier, the Bridge House Hotel in Tullamore said it was cooperating closely with the HSE and have closed temporarily "in the interests of health and safety".
In a statement to RTÉ News, the hotel said all staff at the hotel were being tested as a precautionary measure.
The hotel said the group of up to 40 guests stayed at the hotel and visited several local golf clubs, pubs and a restaurant.
A GP in the midlands has said he has been receiving a significant number of calls in recent days relating to a cluster of Covid-19 cases.
Speaking on RTÉ's Today with Claire Byrne, Dr Declan Scanlon, a GP in the Co Offaly town, said he received a letter from the HSE to inform him of the outbreak of Covid-19 among the golfing group.
He said his practice has been receiving a significant number of calls relating to this incident over the last couple of days.
"This is on top of the normal number of calls we would be getting in any event and it is increasing all the time," he said.
"The letter informs us there had been group who stayed in a local hotel about two weeks ago and a significant number were tested as Covid-19 positive."
Dr Scanlon said he understands there was a cluster identified, with up to 20 tested positive, and that they had played golf in a number of local golf clubs.
He said he was a "bit surprised" to see a group of up to 40.
When asked what it means for Tullamore, he said: "We will pick up the pieces on this and we will do that. We are well prepared to do that."
However, he added that it will increase their workload considerably.
A local Fianna Fáil TD said it is "worrying" to hear about the cluster of cases.
Speaking on the same programme, Barry Cowen said there was a heightened awareness among GPs and the public following the news of positive cases among that group, adding that it was being dealt with appropriately.
He said public health officials were very much in control of this and procedures in relation to contact tracing were being carried out.
Mr Cowen said all the venues where these people were in contact with others had been contacted.
He also said "what has happened has happened", but it is not something you would promote for a group to socialise in this manner.
He said now more than ever it is about reducing social contacts and each and every individual has to take responsibility.
"People I know can be fed up and lethargic but they have to take responsibility," the Laois/Offaly TD said.
"In this instance, it is essential we reduce our contacts to allow GPs deal with increased number of patients and workload."
Additional reporting Dyane Connor