Plans to identify the source of Covid-19 outbreaks have been abandoned amid a sharp escalation in cases.
Contact tracers have placed more than 7,500 calls in a single day to inform people they have the virus.
The process of pinpointing the source of infections, by asking those infected to retrace their contacts over a one-week period rather than 48 hours, was due to be incorporated into the national tracing strategy last month.
However, due to the recent surge in cases, the HSE said it has "not been feasible".
Lauded as a method of enhancing the protocols for tracing, the plan was initially endorsed by the National Public Health Emergency Team (Nphet) last September.
It was delayed due to the spike in cases in October and delays within Ireland's Testing and Tracing programme.
From early last month, as part of a "service improvement plan" for the contact tracing programme, tracers were due to carry out what the HSE described as "source identification" or backwards tracing on all routine cases of Covid-19.
The process would see people who pick up the virus also asked about their movements going back two weeks.
The previous strategy asked people about their close contacts and movements up to 48 hours before they developed symptoms.
The aim of "source identification" is to gather additional information on community transmission cases - where the source of the infection is unknown - and involves asking a series of questions in order to build a more accurate picture of where people are contracting the virus.
It can help with early treatment and to stop the spread to other areas and more people.
The HSE confirmed this week that the contact management programme "cannot prioritise Case Identification and Source Investigation (CSI) at this time".
The programme has been at peak escalation since before Christmas, a spokesperson said, adding: "Undertaking CSI is not feasible with the level of surge being experienced.
"The contact management programme was designed to significantly increase its capacity to deal with 1,500 detected cases every day by the end of December.
"On foot of a range of operational escalations and reconfiguration of service, we are now calling over 6,000 people every day.
"On Monday we called over 7,500 people to inform them of their detected result and take details of their close contacts.
"We are fully focused on responding to all detected cases and informing close contacts so that public health advice will be followed and close contacts will restrict their movements for 14 days."
The HSE said the CSI implementation will be considered when the current surge peak has been reached and the service is stabilised.