Jewish leaders have expressed concerns that the upcoming census may not accurately record the growing number of Jews living in the Republic.
While there has been a noticeable influx of Jews since the last census in 2002, they say that the lack of a separate "Jewish" box under the census form's religion question could mean that some of the newcomers remain statistically invisible.
Jews - and anyone who is not Catholic, Church of Ireland, Methodist, Presbyterian or Muslim - will have to write in their religion under "other", meaning that secular or unaffiliated Jews could go unrecorded.
"It's a pity and unhelpful that it [the CSO] didn't include a category," said Carl Nelkin, vice chairman of the Jewish Representative Council of Ireland. "We're hoping they'll write 'Jewish', but we just don't know. Last time the numbers were encouraging, but if there were a specific category it would help."
The 2002 census recorded a small increase in the Jewish population - up an annual 1.1 per cent to 1,790 - for the first time since 1946. In the last four years more Jews have arrived from Israel, South Africa, North America, Australia and eastern Europe. The largest constituency of new Jewish arrivals came from Israel.
Chief Rabbi Dr Yaakov Pearlman gave a "generous" estimate of the total Jewish population as 2,000, but only about a quarter of that number would be known to the main Orthodox congregation in Terenure, Dublin, he said.
Other Jews could belong to the Progressive synagogue in Rathmines, Dublin, the small Cork community, scattered around the country or unaffiliated.
Apart from the limitations of the census form, another factor complicating any enumeration of the Jewish population is the variety of ways they identify themselves. Depending on whom you ask, Jewishness can mark a religion, an ethnicity or a nationality.
Raphael Siev, Irish Jewish museum curator in Portobello, Dublin, said: "One never knows whether a person is prepared to identify religious affiliation, especially people from eastern Europe."