Seán Ó Neachtain MEP has written to US President-elect Barack Obama urging him to introduce measures to enable an estimated 50,000 undocumented and illegal Irish immigrants to remain in the country legally.
In the letter, Mr Ó Neachtain said the situation of the illegal Irish in America was "unacceptable"
"The American Government is completely and fully within its rights to tighten up security at American airports and ports due to international terrorism threats," he said.
"But I am urging you as the new President of America taking office next Tuesday to show a sense of compassion and understanding of the very difficult situation that many illegal and undocumented Irish people find themselves in at present in America."
"We are now all living in changed circumstances. With the very difficult economic times in Ireland, we are going to have to address this political issue of the undocumented Irish in America with a renewed spirit of determination and purpose. Irish people have been helped before in America via the Donnelly and Morrison laws. We need your political assistance now more than ever.”
Earlier this month, US religious and trade union leaders called on Mr Obama to pass a comprehensive immigration package this year, saying the American economy could not be restored without legalising undocumented immigrants.
"Immigration reform is a necessity in order to fix the American economy," John Wilhelm, president of Unite Here's hospitality division, said during a national teleconference call on immigration reform. The New York-based group represents more than 450,000 workers around the US.
Mr Wilhelm said immigration legislation would help the recovery by eliminating exploitation, increasing wages and tax compliance and placing all workers on a level playing field.
Cardinal Roger Mahony, archbishop of Los Angeles, an outspoken proponent for legalisation, said immigration is a humanitarian and moral issue but is also an economic issue.
"Immigrants must be brought out of the shadows so they can fully contribute to our nation's future economic and social well-being," he said.
Speaking in San Fransisco in December, President Mary McAleese said it was important that efforts continue to reach an agreement to regularise the status of the undocumented Irish.