More than 500 cases were investigated by the Passport Service last year.
The Department of Foreign Affairs says since 2017, large resources have been invested in the integrity section of the Passport Service to clamp down on fraud, including an increase in staff and a large investment in technology.
Details released under the Freedom of Information Act reveal a sharp rise in the number of passport fraud detections since then.
In 2016, the Passport Service investigated 78 suspected cases - but this rose to 504 last year.
A further 240 cases were under investigation in the first six months of this year.
Since 2016, a total of 237 of these cases have been forwarded to the gardaí.
The number of passports cancelled because of suspected fraud has increased by 71 per cent over the past two years - from 76 in 2016 to 130 last year, with a further 46 cancelled by the Passport Service in the first half of this year.