Over three days earlier this month, almost 2 thousand people who'd tested positive were asked to notify their own close contacts.
6 weeks ago, the HSE was making around 8,500 contact tracing calls a week.
But last week, the figure was 38 thousand.
The HSE has admitted the system has struggled - as coronavirus cases have risen across the country.
The executive has told an Oireachtas Committee it's planning to boost the number of contact tracers working in the system by around 300 in the coming weeks.
The HSE also says its contact tracers have had to make some difficult phone calls - with some spending up to an hour on the phone convincing close contacts to get tested.
The HSE has insisted that as of last Friday, the contact tracing system is now back on track.
