A small number of women affected by the cervical screening recall earlier this year have been referred for further investigation.
In June, Northern Ireland health authorities said 150 women were being invited back to have their smear tests redone.
It followed the discovery that the procedure had not been carried out properly.
The women were patients at two GP surgeries.
A spokesperson for the Public Health Agency and Health and Social Care Board said: "The PHA and Health and Social Care Board (HSBC) have been advised that all 150 women at Abbott's Cross Practice in Newtownabbey and Dr McKenna's Practice, Thames Street, Belfast have been invited by their GP for a repeat cervical screening test.
"The women were invited for the retest in June, when the PHA and HSCB were made aware of possible shortcomings in the technique used to conduct a small number of cervical screening tests (commonly referred to as cervical smears), which may not have adequately sampled all of the cervix.
"The majority of results of the repeat tests have been reported as normal.
"A very small number of women have been referred to colposcopy for further investigation.
The PHA and Health and Social Care Board say they are unable to release specific numbers or further details to ensure patient confidentiality is maintained.