An investigation has found that Dublin's Mater Hospital did meet its legal requirements in reporting COVID-19 cases.
However, the HSE chief says data submitted to labs by the hospital at one stage in the process did "not have the full details" of cases.
On Thursday, health authorities were made aware of an extra 244 cases at the facility.
Hospitals are legally obligated to report infectious disease cases as soon as they're aware of them.
An investigation was launched to find out what happened with the cases from the Mater.
Speaking at a HSE briefing today, Chief Executive Paul Reid outlined what they've found out from the investigation in recent days.
He explained: "The information that we have been furnished [with] throughout Friday and yesterday clearly demonstrates that the legal requirement was met.
"However, the information that was submitted to the labs at [one] stage in the process did not have the full details, in particular all the names etc... of those cases.
"Therefore it didn't allow us for the complete correlation of the data at the appropriate time."
He said it's expected the final report into the matter will be finished 'very shortly'.
Mr Reid said health officials are now also seeking assurances from all hospitals that the data being submitted to labs has the 'full and required' details.
The HSE's Chief Clinical Officer Dr Colm Henry stressed the critical information about the cases was given to public health teams for contact tracing.
He said the problem that arose was instead a "data uploading issue".
On Friday, the Mater said it has reported all confirmed cases to health authorities on a daily basis and said it was working with the HSE to find out where the problem arose.
Health Minister Simon Harris, meanwhile, warned that checks would be needed to see if the matter is criminal - saying it was "extremely disappointing" that it happened and that he was awaiting the full report.
