Source:
http://www.inis.gov.ie/en/INIS/Stamp%20 ... mp%200.pdf
Temporary and Limited Permission as indicated by Stamp 0:
On 1 December 2011 the Irish Naturalisation and Immigration Service introduced an additional immigration stamp, namely Stamp 0. This Stamp 0 is simply an administrative change to the immigration stamps and there is no change in policy.
Stamp 0 is a low level immigration permission that allows a person to remain lawfully in Ireland for a specific, temporary and limited purpose. It is not intended to be a pathway to any more permanent form of migration. For example, it could be granted to a service provider sent to Ireland by an overseas company to carry out a particular task for a limited time, visiting academics, or, in exceptional humanitarian circumstances, used to provide for an extended visit beyond the normal 90 days permitted.
Stamp 0 will apply to new cases only. It is not intended to change existing permissions and non-EEA nationals currently holding one of the other immigration stamps will not be eligible to change status to Stamp 0.
Stamp 0 is granted on the strict understanding that the holder receives no State benefits (with the exception of emergency medical assistance). The person must be self-sufficient (through personal resources or support from employer or family) while present in the State. Otherwise immigration permission would not be granted. The person may also be required to have private medical insurance, depending on the duration of their stay. In common with all immigration permissions, breaching a condition of the permission may result in the permission being revoked or not renewed.
There will be no specific application process for a stamp 0. The applicant will seek immigration permission in the normal way. Where permission is granted then the appropriate immigration stamp will be assigned to the person as a means of indicating the category of their immigration permission and the main conditions applicable to it.