ABNORMAL smear tests were found in one in every six women screened for cervical cancer according to the latest report from CervicalCheck.
While more than eight in 10 tests were normal, almost 14pc showed low-grade abnormalities and 1.7pc showed high-grade abnormalities.
CervicalCheck, the national cervical screening programme, was surprised by the high level of abnormalities and says the findings require further investigation.
A total of 104 women were diagnosed with cervical cancer in the 12 months up to September last year when more than 338,670 tests were carried out.
Over 17,430 women had a further test and another 20,769 went for further investigations. Pre-cancerous cells were detected in 8,091 women and 6,930 treatments were given.
The smear test programme was launched four years ago in a bid to reduce the incidence of cervical cancer by detecting changes in the cells of the neck of the womb before they turn cancerous.
The screening programme has processed almost 1.3 million smear tests since it was first launched and more than 830,000 women have availed of the service.
While the scheme is used mostly by women in the 25 to 44-year age group, CervicalCheck says the low proportion of women over 50 coming forward for testing is of concern.
"The programme's aim to achieve 80pc coverage of the eligible population by the end of the second three-year screening round in 2014 remains a challenging target," says Majella Byrne, acting director of the National Cancer Screening Service.
She stresses that a single smear test is of little benefit to women. Regular tests at recommended intervals are necessary to prevent cervical cancer.
"Some women will be recalled for up to 11 routine smear tests and will remain part of the CervicalCheck programme for 35 years. Screening is effective when women continue to be screened regularly."