Almost 1,700 Irish citizens, including religious missionaries, have been refused welfare benefits under restrictions introduced by the Government aimed at preventing "welfare tourism" by immigrants.
A requirement to be habitually resident in Ireland was introduced as a condition for most forms of social assistance before the accession of Poland and other new EU members states in May 2004.
However, latest official figures show that the restrictions have affected 1,684 returned Irish emigrants and other Irish citizens who have not been living here on a regular basis.
This figure includes about 100 religious missionaries who have had claims for non-contributory pension payments rejected during temporary stays in Ireland.
In total about 10 per cent of claims from Irish citizens that required detailed examination to determine if they had complied with habitual residency condition rules have been rejected.
For foreign nationals living here the rejection rate was 25 per cent.
Officials from the Department of Social and Family Affairs say Irish nationals returning to live here on a permanent basis should have no difficulty in meeting the requirements.
EU legislation prohibits discrimination between nationals of different member states in relation to social security entitlements.
If Irish nationals who are not normally resident here were allowed to claim benefits while on short visits home, this entitlement would have to be extended to all EU nationals, officials say.
However, groups such as the Crosscare Migrant Project say the restrictions are often applied inconsistently and are a deterrent for Irish emigrants thinking of returning home.
The group's spokesman, Joe O'Brien, said returning emigrants were advised not to completely cut links with the country they were returning from.
This is because some returning emigrants end up leaving Ireland again within a relatively short period of time.
"This goes directly against what is required of the habitual residency condition. Claimants must demonstrate that they severed links with the US, for example, through a terminated tenancy or closed bank account," he said.
Meanwhile, new guidelines will be introduced within weeks to try to ensure a more consistent application of the habitual residency condition.
Eddie Rice, principal officer at the Department of Social and Family Affairs, told an Oireachtas committee in recent days that guidelines for the scheme were being revised "to ensure consistency in the application of the condition and to take account of the variety of individual situations which can arise".
Staff will receive extensive training "to try to ensure that there is absolute consistency".
Groups such as the Free Legal Advice Centres (Flac) have highlighted cases of rules being applied inconsistently.
Flac has given the example of a woman from outside the EU who was living here for about two years with a sick child. She satisfied the residency condition to receive child benefit, yet she was denied the carer's allowance.
In another case, an Irish emigrant who returned to care for her elderly mother was denied the payment because she had not permanently established herself here.
Noeleen Blackwell of Flac welcomed the review of guidelines and said that child benefit should be excluded from the restrictions because it was affecting a very vulnerable group.