The number of Covid-19 deaths have been overestimated, according to HIQA.
In a study, the watchdog recorded 1,200 excess deaths between March and June compared with the official death toll of more than 1,700.
People who were infected with Covid-19, but died as a result of other reasons are included in the official.
Using data from RIP.ie, there were up to 1,200 more deaths between March and June than there usually would be for the time of year.
The Tanaiste has said the country recorded all deaths in every setting, and included people with terminal illnesses who died with Covid-19 – but not of it.
Dr Conor Teljeur is Chief Scientist with HIQA – he explains what public health doctors can learn from the figures.
The CSO has also released data on death rates from Covid-19, which calculates a similar number of excess deaths.
It says it is possible there will be a lower death rate later in the year because of the high numbers of elderly people and those in nursing homes who died after testing positive for coronavirus.