The campaign to have undocumented migrants given legal status will today present a petition with 4,000 signatures to the Department of Justice.
The Migrants Rights Centre Ireland has estimated there are 30,000 undocumented people living here. It says many of them are working, paying taxes and have raised families in Ireland.
The centre wants Justice Minister Alan Shatter to introduce a "regularisation scheme" that would allow these migrants to live "within the system".
Community worker Edel McGinley said some migrants came to Ireland on the promise of work visas, and have been exploited by employers.
"Giving people the legal right to work will also clamp down on unscrupulous employers," she said.