Ten women have died under the care of maternity units last year – a figure that is 10 times higher than the "official" number reported by the Central Statistics Office.
And a total of 22 women have died under the care of maternity units in a two-year period.
Confirming last year's death toll, the HSE said it cannot give any breakdown of the hospitals involved or the medical causes of the deaths.
This is the first time the HSE has released annual national figures for maternal deaths and they conflict with statistics from the Central Statistics office which recorded just one maternity death last year, believed to be that of Savita Halappanavar.
The HSE has refused to give further details claiming that because the figures are small "there is a possibility that individual women could be identified and this would amount to the release of personal information".
However, it is already known, where eight of the deaths occurred.
These include three at Cork University Maternity Hospital, two at the Rotunda Hospital in Dublin and two at the capital's Coombe Hospital.
Ms Halappanavar also died at University Hospital Galway.
The HSE told irishhealth.com it did not collate national figures for maternal deaths prior to 2011 and the new figures were based on information it recently received from the health and safety body HIQA.
Of the 12 deaths in 2011, six are known to have taken place at Dublin maternity hospitals. The HSE and the Central Statistics Office use different criteria for the definition of "direct" and "indirect" maternal deaths which may account for the statistical differences.
Although there have been 22 maternal deaths in the past two years, Ireland's mortality rate is still regarded as low by international standards and is lower than the UK or America.