The Health Service Executive's National Screening Service has issued a letter to doctors and other staff, explaining that the latest cervical screening problem relates to the years 2015 to 2018.
This period is before the surge in CervicalCheck screening requests which occurred from April last year, after the Government offered free repeat screening for women.
The letter states that: "Based on our current assessment of the information provided by Quest Laboratories, we expect that up to 6,000 women will likely be called for a repeat smear test."
The letter from Frances McNamara, Head of Screening at the National Screening Service, said that an issue had arisen with a number of HPV screening tests carried out on smear tests by one of its laboratories.
The HSE letter said that evidence showed that these tests are likely to remain effective outside of the manufacture's recommended time frame.
It said that as a precautionary measure, around 6,000 women will be asked to attend their GP for a repeat smear test.
"We expect to issue letters to women affected, and their GPs, by late next week", it added.
The letter also contained an apology for the fact that some staff may have become aware of the issue in the media.
It said this was not the intention of the HSE, which had planned formal communication to women and their GPs and others in advance of public communication.
