The Data Protection Commissioner has told the HSE it did not breach any laws by informing some employers of their employees' Covid-19 test results.
The practice was temporarily suspended last month after it was criticised by the Chief Medical Officer Dr Tony Holohan for breaching confidentiality.
The HSE said employers are only informed in exceptional circumstances.
CEO Paul Reid said all data is handled sensitively.
He said: "We've received very early reassurances from the Data Protection Commissioner data breaches didn't occur in these cases and that also we've received very strong legal advice to give us reassurance of same.
"However, we do want to ensure that we do this properly and we are finalising and developing standard operation procedures so that it is done in an exceptional manner."
The issue could have an impact on the uptake of the long-awaited contact tracing app, but Mr Reid is assuring that the HSE will have no access to personal data.
Mr Reid said: "The data is not held on the central health systems. It is in other countries, on ours, it will be held on the person's phone so the data will not be held centrally and can't be used centrally."
The app is undergoing testing and will go to Government for approval this month before being rolled out.