A confidential report prepared by the Blood Bank has found there is no evidence to suggest that women infected with Hepatitis C - outside of two specified risk periods - contracted the virus from the Irish anti-D blood product.
Groups representing those infected have dismissed the finding and demanded the Minister for Health hold an independent inquiry.
Anti-D is a blood product given to a mother if her blood tests rhesus negative but her new child tests rhesus positive.
Without it, the mother's body could develop antibodies which would attack the red cells of a foetus from any subsequent pregnancy, leading to the death of the baby.
In the early 1990s, the Blood Bank screened more than 65,000 women after it was revealed that some of the anti-D it manufactured had become infected with the sometimes lethal Hepatitis C virus.
The investigation identified two sources of contamination and established that most women were infected between May 1977 to July 1979 and March 1991 and February 1994.
A major source of controversy since then has been the dozens of women who tested positive for Hepatitis C, but outside the two risk periods.
The Blood Bank's deputy medical director, Dr Emer Lawlor, undertook an investigation into whether or not these infections could have been caused by Irish anti-D.
In a confidential report seen by RTÉ News, Dr Lawlor found that 'detailed investigation of donors to the pool, the anti-D product and the sequencing and epidemiology on the recipients do not support the hypothesis that anti-D outside the risk years … was infected with Hepatitis C'.