The Health Service Executive says it is recruiting an extra 800 people to work in Covid-19 test and tracing.
It has said that its contact tracing teams have faced unprecedented pressures this month due to the increasing positivity rate.
Earlier, Clinical Lead for the Health Service Executive's Contact Management Programme Dr Sarah Doyle said about 2,000 people, aged between 19-74 years who received a positive test result for Covid-19 last weekend, were being asked to alert their close contacts they have the virus.
As first reported by The Irish Times, the people involved were due to receive a text message today, which could be forwarded with advice for anyone they deem to be a close contact.
Between last Friday and Sunday, more than 3,000 Covid-19 cases were confirmed and people with a positive test result over the three days were notified by text.
Instead of the usual contact tracing involving phone calls, they were to receive a second text today.
In the message, the people who tested positive for the virus were to be asked to send on a message to their own close contacts - people they have spent more than 15 minutes with - alerting them to restrict their movements and to immediately contact their GP to arrange a test.
Dr Doyle said "it's not obviously equivalent to receiving a call from the contact tracing team" but "it is still an effort to advise people of the situation" and to identify their close contacts and forward on this message.
She said this is about identifying as many people at risk of spread of infection as possible and ensuring that they do what is needed to limit the spread of infection.
She urged those who receive a positive test result to self isolate so they cut down chains of transmission.
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Speaking on RTÉ's Six One News, Dr Doyle said that up to two weeks ago, the system was dealing with 500 cases a day and this increased rapidly coming up to last weekend.
She said as soon as it became apparent that the numbers from last weekend were causing delays in contacting people, the situation was reviewed and a decision was made on how best to address the problem.
Dr Doyle agreed it is possible that delays in the contact and tracing system could cause more people to be infected, and she said this was the reason a decision was made to ask people to identify their own close contacts and inform them.
She said it was important to re-emphasise that there is a pandemic and we are facing an unprecedented challenge in terms of the spread of infection and the numbers of cases to be contact traced.
She said the response from the HSE and from the Contact Management Programme needs to be appropriate to the incidents of infection and the resources available to manage that.
The HSE said the action is being taken due to the high numbers of people testing positive last weekend and to ensure close contacts receive information as quickly as possible.
It said this once-off temporary measure is being implemented, in consultation with GPs, to ensure those affected are tested as quickly as possible and to support its contact tracing teams, who continue working under significant pressure due to the increasing positivity rate at this point in the pandemic.
HSE Chief Clinical Officer Dr Colm Henry said: "We know that people would prefer a personal call at what can be a worrying time and we would prefer to make those calls and to continue to do that going into the future.
"For this temporary measure, we should reiterate that the contact tracing process has always been led by the information given to us by the people we are calling, so we are confident that the people involved will be able to identify their own contacts and will contact them as soon as possible."
Taoiseach found out through website article
Micheál Martin told the Dáil this afternoon that he got a text yesterday evening with the Irish Times article and said that was when he found out.
The Taoiseach said that the HSE had now "reset the process" and it was managing all the contact tracing from yesterday again as per normal.
Taoiseach Micheál Martin says that the HSE has now "reset the process" and says that they are managing all contact tracing from yesterday as per normal. pic.twitter.com/f4yTbx4d0N— RTÉ News (@rtenews) October 21, 2020
Elsewhere, HSE Midwest Director of Public Health Dr Mai Mannix said that ideally professional contact tracers should be carrying out the work, but this is a temporary situation.
In every call, she said, patients are being asked to identify contacts, which is difficult because they can be stressed over receiving a positive result.
Speaking on RTE's Today with Claire Byrne, she said people tend to let their guard down in terms of their families, but urged everyone to stick to the public guidelines and wash their hands and keep their distance.
Earlier, the National Lead for Testing and Tracing said school going children aged four to 19, and older people who may need direct support, will be dealt with by the HSE's teams of contact tracers.
Speaking on RTÉ's Morning Ireland, Niamh O'Beirne said contact tracing centres have been reconfigured with more technology and an additional 70 staff will be arriving every week for the foreseeable future.
The centres will have the capacity to deal with 1,500 cases and rising every day.
Limitations to use of alternative tests to detect Covid-19
An assessment by the Health Information and Quality Authority has found limitations to the use of alternative tests to detect Covid-19, including rapid tests.
NPHET requested that HIQA carries out a rapid health technology assessment of alternative tests and approaches to the current gold-standard test of PCR.
HIQA has said that based on the scientific literature, international recommendations, and input from the Covid-19 Expert Advisory Group, it is not possible to provide an across-the-board endorsement of specific technologies due to variation in performance of individual tests.
It said that depending on the circumstances, results from a rapid antigen detection test may need to be confirmed with the current PCR test.
Dr Máirín Ryan, HIQA's Director of Health Technology Assessment and Deputy Chief Executive, said: "The evidence shows that effective testing strategies rely on a portfolio of tests, using different technologies that can be applied in different settings and situations.
"There is no single test that is suited to all contexts."
HIQA has advised that the introduction of validated rapid testing in Ireland should now be considered to enhance Covid-19 prevention and control.
Additional reporting Fergal Bowers