The passport office has had to take on temporary staff to deal with a surge in applications from the UK.
Fears of a potential 'Brexit' are thought to be behind the increase.
It comes as the Taoiseach heads to Northern Ireland to call for a remain vote, ahead of Enda Kenny also heading to England and Scotland later this week.
Figures obtained by SKY news show a 25% increase in the number of passport applications from the UK.
In the first five months of 2015, 1518 Britons applied for an Irish passport – that's gone up to 1,901 this year.
The biggest increase was in the month of April as the referendum campaign got underway with a 42% increase compared to last year.
Foreign Affairs Minister Charlie Flanagan says they've had to hire 200 extra temporary staff in the passport office.
Martin O'Neill lives in York in England – he's an Irish and British passport holder – and wants the same for his children.
This afternoon the Taoiseach will deliver a keynote speech in Belfast with the message that a Brexit would result in customs and border checkpoints.
On Thursday Enda Kenny will visit Liverpool, on Friday he'll share a stage with David Cameron in Manchester before travelling to Scotland for a British Irish Council meeting.
