Up to 24 Irish people are understood to be among the 3,500 foreign tourists still unaccounted for four days after the Indian Ocean tsunami.
A spokeswoman for the Department of Foreign Affairs said the figure of "a couple of dozen was a more accurate total" of the number of Irish still missing.
She said the Department was in the process of cross-checking its original list of people missing with phone calls made by the public to gain a more accurate picture of where they stand.
Yesterday the Minister for Foreign Affairs, Mr Dermot Ahern said "relatives of people in the stricken region should understand that communications systems are down in many areas".
The minister added that it could be "days if not weeks before a clearer picture emerges" of how many Irish people have been affected.
The Department is continuing to operate its helpline at 01-4082308, and has appealed to those whose relatives have contacted them to tell the Department.