Over 27,000 people have been left "in limbo" waiting for Foreign Birth applications to be processed.
The Department of Foreign Affairs has stopped processing Foreign Birth Registrations (FBRs) due to the Covid-19 pandemic, amid a flurry of new applications linked to Brexit.
Until 2016, the number of applications for FBR was approximately 6,000 per year.
Since the Brexit referendum, a marked increase in the number of applications has been recorded reaching more than 25,000 in 2018, 14,000 of which were from Great Britain.
Around 19,000 applications were received within the first six months of 2019 alone, more than 11,000 from British citizens. 2019 recorded over 32,000 by year-end. Over 10,000 applications have been submitted to date in 2020.
There are currently 27,000 applications waiting to be processed in total.
Anyone born outside of Ireland can become an Irish citizen if one of their grandparents was born in Ireland, or one of their parents was an Irish citizen at the time of the person's birth, even though they were not born in Ireland.
Once a person is entered onto the FBR they are an Irish citizen and entitled to apply for an Irish passport.
Since the closure of the office, the Minister for Foreign Affairs, Simon Coveney said: "FBR, by its nature, can be a detailed and complex process, often involving official documentation related to three generations and issued by several jurisdictions.
Until 2016, processing time was usually around six months.
Mary Henderson, a solicitor for the Immigrant Council of Ireland says those already in the State waiting for their application to be processed are unlikely to be as affected as those outside the State.
"The most common situation, which occurs frequently, is that often people who come to Ireland to work for a long time become citizens through naturalisation and might have a relationship and a child abroad," she said. "That child is technically an Irish citizen, but cannot get a passport or enter the state permanently without their FBR.
"In some instances, clients who have Irish citizen children want the child to leave the country quickly, whether it's because of war, or nowadays, rising pandemic rates.
"Those children are permitted to travel straight away, and Ireland has to accept that child, whereas a child going through this process is not considered Irish until they get their foreign birth registration. The halting of processing these applications is separating families for longer.
"This is further stressing people in an already difficult family scenario, these are not refugees, these are Irish citizens living here, and their family happens to live in a different country."